WAC 246-290-010 Definitions. Abbreviations and acronyms:

аааа ADD - average day demand;

аааа AG - air gap;

аааа ANSI - American National Standards Institute;

аааа AVB - atmospheric vacuum breaker;

аааа AWWA - American Water Works Association;

аааа BAT - backflow assembly tester;

аааа C - residual disinfectant concentration in mg/L;

аааа CCS - cross-connection control specialist;

аааа CFR - code of federal regulations;

аааа CPE - comprehensive performance evaluation;

аааа CT - the mathematical product in mg/L - minutes of "C" and "T";

аааа CTA - comprehensive technical assistance;

аааа CWSSA - critical water supply service area;

аааа DBPs - disinfection by-products;

аааа DCDA - double check detector assembly;

аааа DCVA - double check valve assembly;

аааа DVGW - Deutsche Vereinigung des Gas und Wasserfaches;

аааа EPA - Environmental Protection Agency;

аааа ERU - equivalent residential unit;

аааа gph - gallons per hour;

аааа gpm - gallons per minute;

аааа GAC - granular activated carbon;

аааа GAC10 - granular activated carbon with ten-minute empty bed contact time based on average daily flow and one hundred eighty-day reactivation frequency;

аааа GWI - ground water under the direct influence of surface water;

аааа HAA5 - haloacetic acids (five);

аааа HPC - heterotrophic plate count;

аааа IAPMO - International Association of Plumbing and Mechanical Officials;

аааа kPa - kilo pascal (SI units of pressure);

аааа MCL - maximum contaminant level;

аааа MDD - maximum day demand;

аааа mg/L - milligrams per liter (1 mg/L = 1 ppm);

аааа mL - milliliter;

аааа mm - millimeter;

аааа MRDL - maximum residual disinfectant level;

аааа MRDLG - maximum residual disinfectant level goal;

аааа MTTP - maximum total trihalomethane potential;

аааа NSF - NSF International (formerly known as the National Sanitation Foundation (NSF));

аааа NTNC - nontransient noncommunity;

аааа NTU - nephelometric turbidity unit;

аааа ONORM - Osterreichisches Normungsinstitut;

аааа PAA - project approval application;

аааа pCi/L - picocuries per liter;

аааа PHD - peak hourly demand;

аааа ppm - parts per million (1 ppm = 1 mg/L);

аааа psi - pounds per square inch;

аааа PVBA - pressure vacuum breaker assembly;

аааа RPBA - reduced pressure backflow assembly;

аааа RPDA - reduced pressure detector assembly;

аааа SAL - state advisory level;

аааа SCA - sanitary control area;

аааа SDWA - Safe Drinking Water Act;

аааа SEPA - State Environmental Policy Act;

аааа SOC - synthetic organic chemical;

аааа SMA - satellite management agency;

аааа SPI - special purpose investigation;

аааа SRF - state revolving fund;

аааа SUVA - specific ultraviolet absorption;

аааа SVBA - spill resistant vacuum breaker assembly;

аааа SWTR - surface water treatment rule;

аааа T - disinfectant contact time in minutes;

аааа TTHM - total trihalomethane;

аааа TNC - transient noncommunity;

аааа TNTC - too numerous to count;

аааа TOC - total organic carbon;

аааа ug/L - micrograms per liter;

аааа UL - Underwriters Laboratories, Inc.;

аааа umhos/cm - micromhos per centimeter;

аааа UPC - Uniform Plumbing Code;

аааа UTC - utilities and transportation commission;

аааа VOC - volatile organic chemical;

аааа WAC - Washington Administrative Code;

аааа WFI - water facilities inventory form;

аааа WHPA - wellhead protection area; and

аааа WUE - water use efficiency.

аааа "Acute" means posing an immediate risk to human health.

аааа "Alternative filtration technology" means a filtration process for substantial removal of particulates (generally > 2 log Giardia lamblia cysts and ≥ 2-log removal of Cryptosporidium oocysts) by other than conventional, direct, diatomaceous earth, or slow sand filtration processes.

аааа "Analogous treatment system" means an existing water treatment system that has unit processes and source water quality characteristics that are similar to a proposed treatment system.

аааа "Approved air gap" means a physical separation between the free-flowing end of a potable water supply pipeline and the overflow rim of an open or nonpressurized receiving vessel. To be an air gap approved by the department, the separation must be at least:

аааа Twice the diameter of the supply piping measured vertically from the overflow rim of the receiving vessel, and in no case be less than one inch, when unaffected by vertical surfaces (sidewalls); and:

аааа Three times the diameter of the supply piping, if the horizontal distance between the supply pipe and a vertical surface (sidewall) is less than or equal to three times the diameter of the supply pipe, or if the horizontal distance between the supply pipe and intersecting vertical surfaces (sidewalls) is less than or equal to four times the diameter of the supply pipe and in no case less than one and one-half inches.

аааа "Approved atmospheric vacuum breaker (AVB)" means an AVB of make, model, and size that is approved by the department. AVBs that appear on the current approved backflow prevention assemblies list developed by the University of Southern California Foundation for Cross-Connection Control and Hydraulic Research or that are listed or approved by other nationally recognized testing agencies (such as IAPMO, ANSI, or UL) acceptable to the authority having jurisdiction are considered approved by the department.

аааа "Approved backflow preventer" means an approved air gap, an approved backflow prevention assembly, or an approved AVB. The terms "approved backflow preventer," "approved air gap," or "approved backflow prevention assembly" refer only to those approved backflow preventers relied upon by the purveyor for the protection of the public water system. The requirements of WAC 246-290-490 do not apply to backflow preventers installed for other purposes.

аааа "Approved backflow prevention assembly" means an RPBA, RPDA, DCVA, DCDA, PVBA, or SVBA of make, model, and size that is approved by the department. Assemblies that appear on the current approved backflow prevention assemblies list developed by the University of Southern California Foundation for Cross-Connection Control and Hydraulic Research or other entity acceptable to the department are considered approved by the department.

аааа "As-built drawing" means the drawing created by an engineer from the collection of the original design plans, including changes made to the design or to the system, that reflects the actual constructed condition of the water system.

аааа "Authority having jurisdiction" (formerly known as local administrative authority) means the local official, board, department, or agency authorized to administer and enforce the provisions of the Uniform Plumbing Code as adopted under chapter 19.27 RCW.

аааа "Authorized agent" means any person who:

аааа Makes decisions regarding the operation and management of a public water system whether or not he or she is engaged in the physical operation of the system;

аааа Makes decisions whether to improve, expand, purchase, or sell the system; or

аааа Has discretion over the finances of the system.

аааа "Authorized consumption" means the volume of metered and unmetered water used for municipal water supply purposes by consumers, the purveyor, and others authorized to do so by the purveyor, including, but not limited to, fire fighting and training, flushing of mains and sewers, street cleaning, and watering of parks and landscapes. These volumes may be billed or unbilled.

аааа "Average day demand (ADD)" means the total quantity of water use from all sources of supply as measured or estimated over a calendar year divided by three hundred sixty-five. ADD is typically expressed as gallons per day (gpd) per equivalent residential unit (ERU).

аааа "Backflow" means the undesirable reversal of flow of water or other substances through a cross-connection into the public water system or consumer's potable water system.

аааа "Backflow assembly tester" means a person holding a valid BAT certificate issued under chapter 246-292 WAC.

аааа "Backpressure" means a pressure (caused by a pump, elevated tank or piping, boiler, or other means) on the consumer's side of the service connection that is greater than the pressure provided by the public water system and which may cause backflow.

аааа "Backsiphonage" means backflow due to a reduction in system pressure in the purveyor's distribution system and/or consumer's water system.

аааа "Bag filter" means a pressure-driven separation device that removes particulate matter larger than 1 micrometer using an engineered porous filtration media. They are typically constructed of a nonrigid, fabric filtration media housed in a pressure vessel in which the direction of flow is from the inside of the bag to outside.

аааа "Bank filtration" means a water treatment process that uses a well to recover surface water that has naturally infiltrated into ground water through a river bed or bank(s). Infiltration is typically enhanced by the hydraulic gradient imposed by a nearby pumping water supply or other well(s).

аааа "Best available technology" means the best technology, treatment techniques, or other means that EPA finds, after examination for efficacy under field conditions, are available, taking cost into consideration.

аааа "Blended sample" means a sample collected from two or more individual sources at a point downstream of the confluence of the individual sources and prior to the first connection.

аааа "C" means the residual disinfectant concentration in mg/L at a point before or at the first consumer.

аааа "Cartridge filter" means a pressure-driven separation device that removes particulate matter larger than 1 micrometer using an engineered porous filtration media. They are typically constructed as rigid or semi-rigid, self-supporting filter elements housed in pressure vessels in which flow is from the outside of the cartridge to the inside.

аааа "Category red operating permit" means an operating permit identified under chapter 246-294 WAC. Placement in this category results in permit issuance with conditions and a determination that the system is inadequate.

аааа "Chemical contaminant treatment facility" means a treatment facility specifically used for the purpose of removing chemical contaminants.

аааа "Clarification" means a treatment process that uses gravity (sedimentation) or dissolved air (flotation) to remove flocculated particles.

аааа "Closed system" means any water system or portion of a water system in which water is transferred to a higher pressure zone closed to the atmosphere, such as when no gravity storage is present.

аааа "Coagulant" means a chemical used in water treatment to destabilize particulates and accelerate the rate at which they aggregate into larger particles.

аааа "Coagulation" means a process using coagulant chemicals and rapid mixing to destabilize colloidal and suspended particles and agglomerate them into flocs.

аааа "Combination fire protection system" means a fire sprinkler system that:

аааа Is supplied only by the purveyor's water;

аааа Does not have a fire department pumper connection; and

аааа Is constructed of approved potable water piping and materials that serve both the fire sprinkler system and the consumer's potable water system.

аааа "Completely treated water" means water from a surface water source, or a ground water source under the direct influence of surface water (GWI) source that receives filtration or disinfection treatment that fully complies with the treatment technique requirements of Part 6 of this chapter as determined by the department.

аааа "Composite sample" means a sample in which more than one source is sampled individually by the water system and then composited by a certified laboratory by mixing equal parts of water from each source (up to five different sources) and then analyzed as a single sample.

аааа "Comprehensive monitoring plan" means a schedule that describes both the frequency and appropriate locations for sampling of drinking water contaminants as required by state and federal rules.

аааа "Comprehensive performance evaluation (CPE)" means a thorough review and analysis of a treatment plant's performance-based capabilities and associated administrative, operation and maintenance practices. It is conducted to identify factors that may be adversely impacting a plant's capability to achieve compliance and emphasizes approaches that can be implemented without significant capital improvements. The comprehensive performance evaluation must consist of at least the following components: Assessment of plant performance; evaluation of major unit processes; identification and prioritization of performance limiting factors; assessment of the applicability of comprehensive technical assistance; and preparation of a CPE report.

аааа "Comprehensive technical assistance (CTA)" means technical assistance intended to identify specific steps that may help a water treatment plant overcome operational or design limitations identified during a comprehensive performance evaluation.

аааа "Confirmation" means to demonstrate the accuracy of results of a sample by analyzing another sample from the same location within a reasonable period of time, generally not to exceed two weeks. Confirmation is when analysis results fall within plus or minus thirty percent of the original sample results.

аааа "Confluent growth" means a continuous bacterial growth covering a portion or the entire filtration area of a membrane filter in which bacterial colonies are not discrete.

аааа "Construction completion report" means a form provided by the department and completed for each specific construction project to document:

аааа Х Project construction in accordance with this chapter and general standards of engineering practice;

аааа Х Physical capacity changes; and

аааа Х Satisfactory test results.

аааа The completed form must be stamped with an engineer's seal, and signed and dated by a professional engineer.

аааа "Consumer" means any person receiving water from a public water system from either the meter, or the point where the service line connects with the distribution system if no meter is present. For purposes of cross-connection control, "consumer" means the owner or operator of a water system connected to a public water system through a service connection.

аааа "Consumer's water system," as used in WAC 246-290-490, means any potable and/or industrial water system that begins at the point of delivery from the public water system and is located on the consumer's premises. The consumer's water system includes all auxiliary sources of supply, storage, treatment, and distribution facilities, piping, plumbing, and fixtures under the control of the consumer.

аааа "Contaminant" means a substance present in drinking water that may adversely affect the health of the consumer or the aesthetic qualities of the water.

аааа "Contingency plan" means that portion of the wellhead protection program section of the water system plan or small water system management program that addresses the replacement of the major well(s) or wellfield in the event of loss due to ground water contamination.

аааа "Continuous monitoring" means determining water quality with automatic recording analyzers that operate without interruption twenty-four hours per day.

аааа "Conventional filtration treatment" means a series of processes including coagulation, flocculation, clarification, and filtration that together result in substantial particulate removal in compliance with Part 6 of this chapter.

аааа "Cost-effective" means the benefits exceed the costs.

аааа "Council" means the Washington state building code council under WAC 51-04-015(2).

аааа "Critical water supply service area (CWSSA)" means a geographical area which is characterized by a proliferation of small, inadequate water systems, or by water supply problems which threaten the present or future water quality or reliability of service in a manner that efficient and orderly development may best be achieved through coordinated planning by the water utilities in the area.

аааа "Cross-connection" means any actual or potential physical connection between a public water system or the consumer's water system and any source of nonpotable liquid, solid, or gas that could contaminate the potable water supply by backflow.

аааа "Cross-connection control program" means the administrative and technical procedures the purveyor implements to protect the public water system from contamination via cross-connections as required in WAC 246-290-490.

аааа "Cross-connection control specialist" means a person holding a valid CCS certificate issued under chapter 246-292 WAC.

аааа "Cross-connection control summary report" means the annual report that describes the status of the purveyor's cross-connection control program.

аааа "CT" or "CTcalc" means the product of "residual disinfectant concentration" (C) and the corresponding "disinfectant contact time" (T) i.e., "C" x "T."

аааа "CT_99.9" means the CT value required for 99.9 percent (3 log) inactivation of Giardia lamblia cysts.

аааа "CTreq" means the CT value a system shall provide to achieve a specific percent inactivation of Giardia lamblia cysts or other pathogenic organisms of health concern as directed by the department.

аааа "Curtailment" means short-term, infrequent actions by a purveyor and its consumers to reduce their water use during or in anticipation of a water shortage.

аааа "Dead storage" means the volume of stored water not available to all consumers at the minimum design pressure under WAC 246-290-230 (5) and (6).

аааа "Demand forecast" means an estimate of future water system water supply needs assuming historically normal weather conditions and calculated using numerous parameters, including population, historic water use, local land use plans, water rates and their impacts on consumption, employment, projected water use efficiency savings from implementation of a water use efficiency program, and other appropriate factors.

аааа "Department" means the Washington state department of health or health officer as identified in a joint plan of operation under WAC 246-290-030(1).

аааа "Design and construction standards" means department design guidance and other peer reviewed documents generally accepted by the engineering profession as containing fundamental criteria for design and construction of water facility projects. Design and construction standards are comprised of performance and sizing criteria and reference general construction materials and methods.

аааа "Diatomaceous earth filtration" means a filtration process for substantial removal of particulates (> 2 log Giardia lamblia cysts) in which:

аааа A precoat cake of graded diatomaceous earth filter media is deposited on a support membrane (septum); and

аааа Water is passed through the cake on the septum while additional filter media, known as body feed, is continuously added to the feed water to maintain the permeability of the filter cake.

аааа "Direct filtration" means a series of processes including coagulation, flocculation, and filtration (but excluding sedimentation) that together result in substantial particulate removal in compliance with Part 6 of this chapter.

аааа "Direct service connection" means a service hookup to a property that is contiguous to a water distribution main and where additional distribution mains or extensions are not needed to provide service.

аааа "Disinfectant contact time (T in CT)" means: When measuring the first or only C, the time in minutes it takes water to move from the point of disinfectant application to a point where the C is measured; and

аааа For subsequent measurements of C, the time in minutes it takes water to move from one C measurement point to the C measurement point for which the particular T is being calculated.

аааа "Disinfection" means the use of chlorine or other agent or process the department approves for killing or inactivating microbiological organisms, including pathogenic and indicator organisms.

аааа "Disinfection profile" means a summary of Giardia lamblia inactivation through a surface water treatment plant.

аааа "Distribution coliform sample" means a sample of water collected from a representative location in the distribution system at or after the first service and analyzed for coliform presence in compliance with this chapter.

аааа "Distribution-related projects" means distribution projects such as storage tanks, booster pump facilities, transmission mains, pipe linings, and tank coating. It does not mean source of supply (including interties) or water quality treatment projects.

аааа "Distribution system" means all piping components of a public water system that serve to convey water from transmission mains linked to source, storage and treatment facilities to the consumer excluding individual services.

аааа "Domestic or other nondistribution system plumbing problem," means contamination of a system having more than one service connection with the contamination limited to the specific service connection from which the sample was taken.

аааа "Duplicate (verification) sample" means a second sample collected at the same time and location as the first sample and used for verification.

аааа "Elected governing board" means the elected officers with ultimate legal responsibility for operational, technical, managerial, and financial decisions for a public water system.

аааа "Emergency" means an unforeseen event that causes damage or disrupts normal operations and requires immediate action to protect public health and safety.

аааа "Emergency source" means any source that is approved by the department for emergency purposes only, is not used for routine or seasonal water demands, is physically disconnected, and is identified in the purveyor's emergency response plan.

аааа "Engineering design review report" means a form provided by the department and completed for a specific distribution-related project to document:

аааа Х Engineering review of a project report and/or construction documents under the submittal exception process in WAC 246-290-125(3); and

аааа Х Design in accordance with this chapter and general standards of engineering practice.

аааа The completed form must be stamped with engineer's seal, and signed and dated by a professional engineer.

аааа "Equalizing storage" means the volume of storage needed to supplement supply to consumers when the peak hourly demand exceeds the total source pumping capacity.

аааа "Equivalent residential unit (ERU)" means a system-specific unit of measure used to express the amount of water consumed by a typical full-time single family residence.

аааа "Existing service area" means a specific area within which direct service or retail service connections to customers of a public water system are currently available.

аааа "Expanding public water system" means a public water system installing additions, extensions, changes, or alterations to their existing source, transmission, storage, or distribution facilities that will enable the system to increase in size its existing service area and/or its number of approved service connections. Exceptions:

аааа A system that connects new approved individual retail or direct service connections onto an existing distribution system within an existing service area; or

аааа A distribution system extension in an existing service area identified in a current and approved water system plan or project report.

аааа "Filter profile" means a graphical representation of individual filter performance in a direct or conventional surface water filtration plant, based on continuous turbidity measurements or total particle counts versus time for an entire filter run, from startup to backwash inclusively, that includes an assessment of filter performance while another filter is being backwashed.

аааа "Filtration" means a process for removal of particulate matter from water by passage through porous media.

аааа "Financial viability" means the capability of a water system to obtain sufficient funds to construct, operate, maintain, and manage a public water system, on a continuing basis, in full compliance with federal, state, and local requirements.

аааа "Finished water" means water introduced into a public water system's distribution system and is intended for distribution and consumption without further treatment, except as treatment necessary to maintain water quality in the distribution system (e.g., booster disinfection, addition of corrosion control chemicals).

аааа "Finished water storage facility" means a water storage structure that is integrated with a water system's distribution network to provide for variable system demands including, but not limited to, daily equalizing storage, standby storage, or fire reserves, or to provide for disinfectant contact time.

аааа "Fire flow" means the maximum rate and duration of water flow needed to suppress a fire under WAC 246-293-640 or as required under local fire protection authority standards.

аааа "Fire suppression storage" means the volume of stored water available during fire suppression activities to satisfy minimum pressure requirements per WAC 246-290-230.

аааа "First consumer" means the first service connection associated with any source (i.e., the point where water is first withdrawn for human consumption, excluding connections where water is delivered to another water system covered by these regulations).

аааа "Flocculation" means a process enhancing agglomeration and collection of colloidal and suspended particles into larger, more easily settleable or filterable particles by gentle stirring.

аааа "Flowing stream" means a course of running water flowing in a definite channel.

аааа "Flow-through fire protection system" means a fire sprinkler system that:

аааа Is supplied only by the purveyor's water;

аааа Does not have a fire department pumper connection;

аааа Is constructed of approved potable water piping and materials to which sprinkler heads are attached; and

аааа Terminates at a connection to a toilet or other plumbing fixture to prevent stagnant water.

аааа "Forecasted demand characteristics" means the factors that may affect a public water system's projected water needs.

аааа "Future service area" means a specific area a public water system plans to provide water service. This is determined by a written agreement between purveyors under WAC 246-293-250 or by the purveyor's elected governing board or governing body if not required under WAC 246-293-250.

аааа "Governing body" means the individual or group of individuals with ultimate legal responsibility for operational, technical, managerial, and financial decisions for a public water system.

аааа "Grab sample" means a water quality sample collected at a specific instant in time and analyzed as an individual sample.

аааа "Ground water under the direct influence of surface water (GWI)" means any water beneath the surface of the ground that the department determines has the following characteristics:

аааа Significant occurrence of insects or other macroorganisms, algae, or large-diameter pathogens such as Giardia lamblia or, Cryptosporidium; or

аааа Significant and relatively rapid shifts in water characteristics such as turbidity, temperature, conductivity, or pH closely correlating to climatological or surface water conditions where natural conditions cannot prevent the introduction of surface water pathogens into the source at the system's point of withdrawal.

аааа "Guideline" means a department document assisting the purveyor in meeting a rule requirement.

аааа "Health officer" means the health officer of the city, county, city-county health department or district, or an authorized representative.

аааа "Heterotrophic Plate Count (HPC)" means a procedure to measure a class of bacteria that use organic nutrients for growth. The density of these bacteria in drinking water is measured as colony forming units per milliliter and is referred to as the HPC.

аааа "High health cross-connection hazard" means a cross-connection involving any substance that could impair the quality of potable water and create an actual public health hazard through injury, poisoning, or spread of disease.

аааа "Human consumption" means the use of water for drinking, bathing or showering, hand washing, food preparation, cooking, or oral hygiene.

аааа "Hydraulic analysis" means the study of a water system's distribution main and storage network to determine present or future adequacy for provision of service to consumers within the established design parameters for the system under peak flow conditions, including fire flow. The analysis is used to establish any need for improvements to existing systems or to substantiate adequacy of design for distribution system components such as piping, elevated storage, booster stations or similar facilities used to pump and convey water to consumers.

аааа "Inactivation" means a process which renders pathogenic microorganisms incapable of producing disease.

аааа "Inactivation ratio" means the ratio obtained by dividing CTcalc by CTreq.

аааа "Incompletely treated water" means water from a surface or GWI source that receives filtration and/or disinfection treatment that does not fully comply with the treatment technique requirements of Part 6 of this chapter as determined by the department.

аааа "In-line filtration" means a series of processes, including coagulation and filtration (but excluding flocculation and sedimentation) that together result in particulate removal.

аааа "In-premises protection" means a method of protecting the health of consumers served by the consumer's potable water system, located within the property lines of the consumer's premises by the installation of an approved air gap or backflow prevention assembly at the point of hazard, which is generally a plumbing fixture.

аааа "Intertie" means an interconnection between public water systems permitting the exchange or delivery of water between those systems.

аааа "Lake or reservoir" means a natural or man-made basin or hollow on the earth's surface in which water collects or is stored that may or may not have a current or single direction of flow.

аааа "Legionella" means a genus of bacteria containing species which cause a type of pneumonia called Legionnaires' Disease.

аааа "Limited alternative to filtration" means a process that ensures greater removal and/or inactivation efficiencies of pathogenic organisms than would be achieved by the combination of filtration and chlorine disinfection.

аааа "Local plans and regulations" means any comprehensive plan or development regulation adopted under chapter 36.70A RCW or any other applicable comprehensive plan, land use plan, or development regulation adopted by a city, town, or county for the applicable service area.

аааа "Low cross-connection hazard" means a cross-connection that could impair the quality of potable water to a degree that does not create a hazard to the public health, but does adversely and unreasonably affect the aesthetic qualities of potable waters for domestic use.

аааа "Major project" means all construction projects subject to the State Environmental Policy Act (SEPA) under WAC 246-03-030 (3)(a) and include all surface water source development, all water system storage facilities greater than one-half million gallons, new transmission lines longer than one thousand feet and larger than eight inches in diameter located in new rights of way and major extensions to existing water distribution systems involving use of pipes greater than eight inches in diameter, that are designed to increase the existing service area by more than one square mile.

аааа "Mandatory curtailment" means curtailment required by a public water system of specified water uses and consumer classes for a specified period of time.

аааа "Marginal costs" means the costs incurred by producing the next increment of supply.

аааа "Maximum contaminant level (MCL)" means the maximum permissible level of a contaminant in water the purveyor delivers to any public water system user, measured at the locations identified under WAC 246-290-300, Table 3.

аааа "Maximum contaminant level violation" means a confirmed measurement above the MCL and for a duration of time, where applicable, as outlined under WAC 246-290-310.

аааа "Maximum day demand (MDD)" means the highest actual or estimated quantity of water that is, or is expected to be, used over a twenty-four hour period, excluding unusual events or emergencies. MDD is typically expressed as gallons per day per ERU (gpd/ERU).

аааа "Membrane filtration" means a pressure or vacuum driven separation process in which particulate matter larger than 1 micrometer is rejected by an engineered barrier, primarily through a size-exclusion mechanism, and which has a measurable removal efficiency of a target organism that can be verified through the application of a direct integrity test. This definition includes the common membrane technologies of microfiltration, ultrafiltration, nanofiltration, and reverse osmosis.

аааа "Monitoring waiver" means an action taken by the department under WAC 246-290-300 (4)(g) or (8)(f) to allow a water system to reduce specific monitoring requirements based on a determination of low source vulnerability to contamination.

аааа "Municipal water supplier" means an entity that supplies water for municipal water supply purposes.

аааа "Municipal water supply purposes" means a beneficial use of water:

аааа (a) For residential purposes through fifteen or more residential service connections or for providing residential use of water for a nonresidential population that is, on average, at least twenty-five people for at least sixty days a year;

аааа (b) For governmental or governmental proprietary purposes by a city, town, public utility, district, county, sewer district, or water district; or

аааа (c) Indirectly for the purposes in (a) or (b) of this definition through the delivery of treated or raw water to a public water system for such use.

аааа (i) If water is beneficially used under a water right for the purposes listed in (a), (b), or (c) of this definition, any other beneficial use of water under the right generally associated with the use of water within a municipality is also for "municipal water supply purposes," including, but not limited to, beneficial use for commercial, industrial, irrigation of parks and open spaces, institutional, landscaping, fire flow, water system maintenance and repair, or related purposes.

аааа (ii) If a governmental entity holds a water right that is for the purposes listed in (a), (b), or (c) of this definition, its use of water or its delivery of water for any other beneficial use generally associated with the use of water within a municipality is also for "municipal water supply purposes," including, but not limited to, beneficial use for commercial, industrial, irrigation of parks and open spaces, institutional, landscaping, fire flow, water system maintenance and repair, or related purposes.

аааа "Nested storage" means one component of storage is contained within the component of another.

аааа "Nonacute" means posing a possible or less than immediate risk to human health.

аааа "Nonresident" means a person having access to drinking water from a public water system, but who lives elsewhere. Examples include travelers, transients, employees, students, etc.

аааа "Normal operating conditions" means those conditions associated with the designed, day-to-day provision of potable drinking water that meets regulatory water quality standards and the routine service expectations of the system's consumers at all times, including meeting fire flow demands. Operation under conditions such as power outages, floods, or unscheduled transmission or distribution disruptions, even if considered in the system design, are considered abnormal.

аааа "Operational storage" means the volume of distribution storage associated with source or booster pump normal cycling times under normal operating conditions and is additive to the equalizing and standby storage components, and to fire flow storage if this storage component exists for any given tank.

аааа "Peak hourly demand (PHD)" means the maximum rate of water use, excluding fire flow, that can be expected to occur within a defined service area over a continuous sixty minute time period. PHD is typically expressed in gallons per minute (gpm).

аааа "Peak hourly flow" means, for the purpose of CT calculations, the greatest volume of water passing through the system during any one hour in a day.

аааа "Performance criteria" means the level at which a system shall operate in order to maintain system reliability compliance, in accordance with WAC 246-290-420, and to meet consumers' reasonable expectations.

аааа "Permanent residence" means any dwelling that is, or could reasonably be expected to be, occupied on a continuous basis.

аааа "Permanent source" means a public water system supply source that is used regularly each year, and based on expected operational requirements of the system, will be used more than three consecutive months in any twelve-month period. For seasonal water systems that are in operation for less than three consecutive months per year, their sources shall also be considered to be permanent.

аааа "Plant intake" means the works or structures at the head of a conduit through which water is diverted from a source (e.g., river or lake) into the treatment plant.

аааа "Point of disinfectant application" means the point where the disinfectant is added, and where water downstream of that point is not subject to contamination by untreated surface water.

аааа "Population served" means the number of persons, resident and nonresident, having immediate access to drinking water from a public water system, whether or not persons have actually consumed water from that system. The number of nonresidents shall be the average number of persons having immediate access to drinking water on days access was provided during that month. In the absence of specific population data, the number of residents shall be computed by multiplying the number of active services by two and one-half.

аааа "Potable" means water suitable for drinking by the public.

аааа "Potential GWI" means a source identified by the department as possibly under the influence of surface water, and includes, but is not limited to, all wells with a screened interval fifty feet or less from the ground surface at the wellhead and located within two hundred feet of a surface water, and all Ranney wells, infiltration galleries, and springs.

аааа "Premises isolation" means a method of protecting a public water system by installation of approved air gaps or approved backflow prevention assemblies at or near the service connection or alternative location acceptable to the purveyor to isolate the consumer's water system from the purveyor's distribution system.

аааа "Presedimentation" means a preliminary treatment process used to remove gravel, sand, and other particulate material from the source water through settling before the water enters the primary clarification and filtration processes in a treatment plant.

аааа "Pressure filter" means an enclosed vessel containing properly sized and graded granular media through which water is forced under greater than atmospheric pressure.

аааа "Primary disinfection" means a treatment process for achieving inactivation of Giardia lamblia cysts, viruses, or other pathogenic organisms of public health concern to comply with the treatment technique requirements of Part 6 of this chapter.

аааа "Primary standards" means standards based on chronic, nonacute, or acute human health effects.

аааа "Primary turbidity standard" means an accurately prepared formazin solution or commercially prepared polymer solution of known turbidity (prepared in accordance with "standard methods") that is used to calibrate bench model and continuous turbidimeters (instruments used to measure turbidity).

аааа "Project approval application (PAA)" means a department form documenting ownership of water system, design engineer for the project, and type of project.

аааа "Protected ground water source" means a ground water source the purveyor shows to the department's satisfaction as protected from potential sources of contamination on the basis of hydrogeologic data and/or satisfactory water quality history.

аааа "Public forum" means a meeting open to the general public that allows for their participation.

аааа "Public water system" is defined and referenced under WAC 246-290-020.

аааа "Purchased source" means water a purveyor purchases from a public water system not under the control of the purveyor for distribution to the purveyor's consumers.

аааа "Purveyor" means an agency, subdivision of the state, municipal corporation, firm, company, mutual or cooperative association, institution, partnership, or person or other entity owning or operating a public water system. Purveyor also means the authorized agents of these entities.

аааа "Reclaimed water" means effluent derived in any part from sewage from a wastewater treatment system that has been adequately and reliably treated, so that as a result of that treatment, it is suitable for beneficial use or a controlled use that would not otherwise occur, and it is no longer considered wastewater.

аааа "Record drawings" means the drawings bearing the seal and signature of a professional engineer that reflect the modifications made to construction documents, documenting actual constructed conditions of the water system facilities.

аааа "Recreational tract" means an area that is clearly defined for each occupant, but has no permanent structures with internal plumbing, and the area has been declared in the covenants or on the recorded plat in order to be eligible for reduced design considerations.

аааа "Regional public water supplier" means a water system that provides drinking water to one, or more, other public water systems.

аааа "Regularly" means four hours or more per day for four days or more per week.

аааа "Removal credit" means the level (expressed as a percent or log) of Giardia and virus removal the department grants a system's filtration process.

аааа "Repeat sample" means a sample collected to confirm the results of a previous analysis.

аааа "Resident" means an individual living in a dwelling unit served by a public water system.

аааа "Residual disinfectant concentration" means the analytical level of a disinfectant, measured in milligrams per liter, that remains in water following the application (dosing) of the disinfectant after some period of contact time.

аааа "Retail service area" means the specific area defined by the municipal water supplier where the municipal water supplier has a duty to provide service to all new service connections. This area must include the municipal water supplier's existing service area and may also include areas where future water service is planned if the requirements of RCW 43.20.260 are met.

аааа "Same farm" means a parcel of land or series of parcels that are connected by covenants and devoted to the production of livestock or agricultural commodities for commercial purposes and does not qualify as a Group A public water system.

аааа "Sanitary survey" means a review, inspection, and assessment of a public water system by the department or department designee including, but not limited to: Source, facilities, equipment, administration and operation, maintenance procedures, monitoring, recordkeeping, planning documents and schedules, and management practices. The purpose of the survey is to evaluate the adequacy of the water system for producing and distributing safe and adequate drinking water.

аааа "Satellite management agency (SMA)" means a person or entity that is approved by the department to own or operate public water systems on a regional or county-wide basis without the necessity for a physical connection between the systems.

аааа "Seasonal source" means a public water system source used on a regular basis, that is not a permanent or emergency source.

аааа "Secondary standards" means standards based on factors other than health effects.

аааа "Service area" means the specific area or areas a water system currently serves or plans to provide water service. This may be comprised of the existing service area, retail service area, future service area, and include areas where water is provided to other public water systems.

аааа "Service connection" means a connection to a public water system designed to provide potable water to a single family residence, or other residential or nonresidential population. When the connection provides water to a residential population without clearly defined single family residences, the following formulas shall be used in determining the number of services to be included as residential connections on the WFI form:

аааа Divide the average population served each day by two and one-half; or

аааа Using actual water use data, calculate the total ERUs represented by the service connection in accordance with department design guidance.

аааа In no case shall the calculated number of services be less than one.

аааа "Severe health cross-connection hazard" means a cross-connection which could impair the quality of potable water and create an immediate, severe public health hazard through poisoning or spread of disease by contaminants from radioactive material processing plants, nuclear reactors, or wastewater treatment plants.

аааа "Significant noncomplier" means a system that is violating or has violated department rules, and the violations may create, or have created an imminent or a significant risk to human health. The violations include, but are not limited to, repeated violations of monitoring requirements, failure to address an exceedance of permissible levels of regulated contaminants, or failure to comply with treatment technique standards or requirements.

аааа "Simple disinfection" means any form of disinfection that requires minimal operational control in order to maintain the disinfection at proper functional levels, and that does not pose safety concerns that would require special care, equipment, or expertise. Examples include hypochlorination, UV-light, contactor chlorination, or any other form of disinfection practice that is safe to use and easy to routinely operate and maintain.

аааа "Slow sand filtration" means a process involving passage of source water through a bed of sand at low velocity (generally less than 0.10 gpm/ft²) that results in substantial particulate removal (> 2 log Giardia lamblia cysts) by physical and biological mechanisms.

аааа "Societal perspective" means a point of view that includes a broad spectrum of public benefits, including, but not limited to, enhanced system reliability; savings that result from delaying, deferring, or minimizing capital costs; and environmental benefits such as increased water in streams, improvements in aquifer recharge and other environmental factors.

аааа "Source meter" means a meter that measures total output of a water source over specific time periods.

аааа "Source water" means untreated water that is not subject to recontamination by surface runoff and:

аааа For unfiltered systems, enters the system immediately before the first point of disinfectant application; and

аааа For filtered systems, enters immediately before the first treatment unit of a water treatment facility.

аааа "Special purpose investigation (SPI)" means on-site inspection of a public water system by the department or designee to address a potential public health concern, regulatory violation, or consumer complaint.

аааа "Special purpose sample" means a sample collected for reasons other than the monitoring compliance specified in this chapter.

аааа "Spring" means a source of water where an aquifer comes in contact with the ground surface.

аааа "Standard methods" means the book, titled Standard Methods for the Examination of Water and Waste Water, jointly published by the American Public Health Association, American Water Works Association (AWWA), and Water Pollution Control Federation. This book is available through public libraries or may be ordered from AWWA, 6666 West Quincy Avenue, Denver, Colorado 80235. The edition to be used is that specified by EPA for the relevant drinking water parameter in 40 CFR Part 141.

аааа "Standby storage" means the volume of stored water available for use during a loss of source capacity, power, or similar short-term emergency.

аааа "State advisory level (SAL)" means a level established by the department and state board of health for a contaminant without an existing MCL. The SAL represents a level that when exceeded, indicates the need for further assessment to determine if the chemical is an actual or potential threat to human health.

аааа "State board of health" and "board" means the board created by RCW 43.20.030.

аааа "State building code" means the codes adopted by and referenced in chapter 19.27 RCW; the state energy code; and any other codes so designated by the Washington state legislature as adopted and amended by the council.

аааа "State revolving fund (SRF)" means the revolving loan program financed by the state and federal governments and managed by the state for the purpose of assisting water systems to meet their capital needs associated with complying with the federal Safe Drinking Water Act under chapter 246-296 WAC.

аааа "Subpart H System" see definition for "surface water system."

аааа "Surface water" means a body of water open to the atmosphere and subject to surface runoff.

аааа "Surface water system" means a public water system that uses in whole, or in part, source water from a surface supply, or GWI supply. This includes systems that operate surface water treatment facilities, and systems that purchase "completely treated water" (as defined in this subsection). A "surface water system" is also referred to as a "Subpart H System" in some federal regulatory language adopted by reference and the two terms are considered equivalent for the purposes of this chapter.

аааа "Susceptibility assessment" means the completed Susceptibility Assessment Survey Form developed by the department to evaluate the hydrologic setting of the water source and assess its contribution to the source's overall susceptibility to contamination from surface activities.

аааа "Synthetic organic chemical (SOC)" means a manufactured carbon-based chemical.

аааа "System capacity" means the system's operational, technical, managerial, and financial capability to achieve and maintain compliance with all relevant local, state, and federal plans and regulations.

аааа "System physical capacity" means the maximum number of service connections or equivalent residential units (ERUs) that the system can serve when considering the limitation of each system component such as source, treatment, storage, transmission, or distribution, individually and in combination with each other.

аааа "Time-of-travel" means the time required for ground water to move through the water bearing zone from a specific point to a well.

аааа "Too numerous to count (TNTC)" means the total number of bacterial colonies exceeds 200 on a 47-mm diameter membrane filter used for coliform detection.

аааа "Tracer study" means a field study conducted to determine the disinfectant contact time, T, provided by a water system component, such as a clearwell or storage reservoir, used for Giardia lamblia cyst and virus inactivation. The study involves introducing a tracer chemical at the inlet of the contact basin and measuring the resulting outlet tracer concentration as a function of time.

аааа "Transmission line" means pipes used to convey water from source, storage, or treatment facilities to points of distribution or distribution mains, and from source facilities to treatment or storage facilities. This also can include transmission mains connecting one section of distribution system to another section of distribution system as long as this transmission main is clearly defined on the plans and no service connections are allowed along the transmission main.

аааа "Treatment technique requirement" means a department-established requirement for a public water system to provide treatment, such as filtration or disinfection, as defined by specific design, operating, and monitoring requirements. A "treatment technique requirement" is established in lieu of a primary MCL when monitoring for the contaminant is not economically or technologically feasible.

аааа "Trihalomethane (THM)" means one of a family of organic compounds, named as derivatives of methane, where three of the four hydrogen atoms in methane are each substituted by a halogen atom in the molecular structure. THMs may occur when chlorine, a halogen, is added to water containing organic material and are generally found in water samples as disinfection by-products.

аааа "Turbidity event" means a single day or series of consecutive days, not to exceed fourteen, when one or more turbidity measurement each day exceeds 5 NTU.

аааа "Two-stage lime softening" means a process in which chemical addition and hardness precipitation occur in each of two distinct unit clarification processes in series prior to filtration.

аааа "T10" means the time it takes ten percent of the water passing through a system contact tank intended for use in the inactivation of Giardia lamblia cysts, viruses, and other microorganisms of public health concern, as determined from a tracer study conducted at peak hourly flow or from published engineering reports or guidance documents for similarly configured tanks.

аааа "Unapproved auxiliary water supply" means a water supply (other than the purveyor's water supply) on or available to the consumer's premises that is either not approved for human consumption by the health agency having jurisdiction or is not otherwise acceptable to the purveyor.

аааа "Uncovered finished water storage facility" means a tank, reservoir, or other facility used to store water, which will undergo no further treatment to reduce microbial pathogens except residual disinfection and is directly open to the atmosphere without a suitable water-tight roof or cover.

аааа "Uniform Plumbing Code" means the code adopted under RCW 19.27.031(4) and implemented under chapter 51-56 WAC. This code establishes statewide minimum plumbing standards applicable within the property lines of the consumer's premises.

аааа "Used water" means water which has left the control of the purveyor.

аааа "Verification" means to demonstrate the results of a sample to be precise by analyzing a duplicate sample. Verification occurs when analysis results fall within plus or minus thirty percent of the original sample.

аааа "Virus" means a virus of fecal origin which is infectious to humans and transmitted through water.

аааа "Volatile organic chemical (VOC)" means a manufactured carbon-based chemical that vaporizes quickly at standard pressure and temperature.

аааа "Voluntary curtailment" means a curtailment of water use requested, but not required of consumers.

аааа "Waterborne disease outbreak" means the significant occurrence of acute infectious illness, epidemiologically associated with drinking water from a public water system, as determined by the appropriate local health agency or the department.

аааа "Water demand efficiency" means minimizing water use by the public water system's consumers through purveyor sponsored activities that may include, but are not limited to distributing water saving devices, providing rebates or incentives to promote water efficient technologies or by providing water audits to homes, businesses, or landscapes.

аааа "Water facilities inventory (WFI) form" means the department form summarizing each public water system's characteristics.

аааа "Water right" means a permit, claim, or other authorization, on record with or accepted by the department of ecology, authorizing the beneficial use of water in accordance with all applicable state laws.

аааа "Water right self-assessment" means an evaluation of the legal ability of a water system to use water for existing or proposed usages in conformance with state water right laws. The assessment may be done by a water system, a purveyor, the department of ecology, or any combination thereof.

аааа "Watershed" means the region or area that:

аааа Ultimately drains into a surface water source diverted for drinking water supply; and

аааа Affects the physical, chemical, microbiological, and radiological quality of the source.

аааа "Water shortage" means a situation during which the water supplies of a system cannot meet normal water demands for the system, including peak periods.

аааа "Water shortage response plan" means a plan outlining policies and activities to be implemented to reduce water use on a short-term basis during or in anticipation of a water shortage.

аааа "Water supply characteristics" means the factors related to a public water system's source of water supply that may affect its availability and suitability to provide for both short-term and long-term needs. Factors include, but are not limited to, source location, name of any body of water and water resource inventory area from which water is diverted or withdrawn, production capacity, the source's natural variability, the system's water rights for the source, and other legal demands on the source such as water rights for other uses, conditions established to protect species listed under the Endangered Species Act in 50 CFR 17.11; instream flow restrictions established under Title 173 WAC, and any conditions established by watershed plans approved under chapter 90.82 RCW and RCW 90.54.040(1) or salmon recovery plans under chapter 77.85 RCW.

аааа "Water supply efficiency" means increasing a public water system's transmission, storage and delivery potential through activities that may include, but are not limited to system-wide water audits, documenting authorized uses, conducting leak surveys and repairs on meters, lines, storage facilities, and valves.

аааа "Water use efficiency (WUE)" means increasing water supply efficiency and water demand efficiency to minimize water withdrawals and water use.

аааа "Water use efficiency program" means policies and activities focusing on increasing water supply efficiency and water demand efficiency to minimize water withdrawals and water use.

аааа "Well field" means a group of wells one purveyor owns or controls that:

аааа Draw from the same aquifer or aquifers as determined by comparable inorganic chemical analysis and comparable static water level and top of the open interval elevations; and

аааа Discharge water through a common pipe and the common pipe shall allow for collection of a single sample before the first distribution system connection.

аааа "Wellhead protection area (WHPA)" means the portion of a well's, wellfield's or spring's zone of contribution defined using WHPA criteria established by the department.

аааа "Zone of contribution" means the area surrounding a pumping well or spring that encompasses all areas or features that supply ground water recharge to the well or spring.

[Statutory Authority: RCW 70.119A.180 and 43.20.050. 08-03-061, з 246-290-010, filed 1/14/08, effective 2/14/08. Statutory Authority: RCW 70.119A.180. 07-02-025B, з 246-290-010, filed 12/22/06, effective 1/22/07. Statutory Authority: RCW 43.20.050 and 70.119A.080. 04-04-056, з 246-290-010, filed 1/30/04, effective 3/1/04. Statutory Authority: RCW 43.20.050 (2) and (3) and 70.119A.080. 03-08-037, з 246-290-010, filed 3/27/03, effective 4/27/03. Statutory Authority: RCW 43.02.050 [43.20.050]. 99-07-021, з 246-290-010, filed 3/9/99, effective 4/9/99. Statutory Authority: RCW 43.20.050. 94-14-001, з 246-290-010, filed 6/22/94, effective 7/23/94; 93-08-011 (Order 352B), з 246-290-010, filed 3/25/93, effective 4/25/93; 92-04-070 (Order 241B), з 246-290-010, filed 2/4/92, effective 3/6/92. Statutory Authority: Chapter 43.20 RCW. 91-07-031 (Order 150B), з 246-290-010, filed 3/15/91, effective 4/15/91. Statutory Authority: RCW 43.20.050. 91-02-051 (Order 124B), recodified as з 246-290-010, filed 12/27/90, effective 1/31/91. Statutory Authority: P.L. 99-339. 89-21-020 (Order 336), з 248-54-015, filed 10/10/89, effective 11/10/89. Statutory Authority: RCW 34.04.045. 88-05-057 (Order 307), з 248-54-015, filed 2/17/88. Statutory Authority: RCW 43.20.050. 83-19-002 (Order 266), з 248-54-015, filed 9/8/83.]