Washington Administrative Code

(1) General.(a) When an MCL or MRDL violation or SAL exceedance occurs, the purveyor shall take follow-up action as described in this section.(b) When a primary standard violation occurs the purveyor shall:(i) Notify the department under WAC 246-290-480;(ii) Notify the consumers …

(1) The purveyor shall operate the system in accordance with the operations and maintenance program as established in the approved water system plan required under WAC 246-290-100 or the small water system management program under WAC 246-290-105.(2) The operations and maintenanc…

(1) All public water systems shall submit to a sanitary survey conducted by the department, or the department's designee, based upon the following schedule:(a) For community water systems, every three years. In accordance with 40 C.F.R. 141.21 (d)(3), community water systems may …

(1) All public water systems shall provide an adequate quantity and quality of water in a reliable manner at all times consistent with the requirements of this chapter.(2) During normal operating conditions, for both average and peak demand periods, water pressure at the consumer…

(1) No portion of a public water system containing potable water shall be put into service, nor shall service be resumed until the facility has been effectively disinfected.(a) In cases of new construction, drinking water shall not be furnished to the consumer until satisfactory …

(1) Groundwater systems with significant deficiencies identified under WAC 246-290-416, or source fecal contamination as determined under WAC 246-290-300 (3)(h) must:(a) Take one or more of the following corrective actions:(i) Correct all significant deficiencies;(ii) Provide an …

(1) Finished drinking water from chemical contaminant treatment facilities must comply with the minimum water quality standards established in WAC 246-290-310. This section does not apply to facilities used only for corrosion control treatment purposes.(a) The purveyor shall coll…

(1) Purveyors shall obtain written department approval of fluoridation treatment facilities before placing them in service and shall notify the department before discontinuing fluoridation.(2) Where fluoridation is practiced, the optimal fluoride concentration is 0.7 mg/L.(3) To …

(1) Existing uncovered finished water storage facilities shall be operated based on a plan of operation approved by the department.(2) Purveyors with uncovered finished water storage facilities shall have a department-approved plan and schedule to cover all reservoirs on file wit…

(1) Records. The purveyor shall keep the following records of operation and water quality analyses:(a) Bacteriological and turbidity analysis results must be kept for five years. Chemical analysis results must be kept for as long as the system is in operation. Records of source m…

(1) Records. In addition to the requirements of WAC 246-290-480, the purveyor shall keep the following records:(a) Records of corrective actions. For each action, records shall be kept for at least ten years.(b) Records of public notification as required under WAC 246-290-71005 (…

(1) Applicability, purpose, and responsibility.(a) All community water systems shall comply with the cross-connection control requirements specified in this section.(b) All noncommunity water systems shall apply the principles and provisions of this section, including subsection …

(1) Production:(a) The volume of water produced or purchased must be measured using a source meter or other meter installed upstream of the distribution system.(b) The requirements of this section do not alter any source metering regulations adopted by either the department of he…

If any provision of this chapter or its application to any person or circumstances is held invalid, the remainder of this chapter, or the application of the provision to other persons or circumstances, shall not be affected.[Statutory Authority: RCW 43.20.050. WSR 91-02-051 (Orde…

(1) Part 6 of chapter 246-290 WAC establishes filtration and disinfection as treatment technique requirements for water systems using surface or GWI sources. The Part 6 treatment technique requirements are established in lieu of maximum contaminant levels (MCLs) for the following…

(1) The requirements of Part 6 of this chapter apply to water systems that:(a) Use surface sources or groundwater sources under the direct influence of surface water (GWI); or(b) Purchase surface or GWI water from an approved public water system or other entity acceptable to the …

(1) The purveyor shall provide treatment for surface and GWI sources consistent with the treatment technique requirements specified in Part 6 of this chapter.(2) The purveyor shall install and properly operate water treatment processes to achieve at least:(a) 99.9 percent (3-log)…

(1) A treatment technique violation shall be considered a violation of a primary drinking water standard and in the case of an unfiltered system, may result in the purveyor of an unfiltered system being required to install filtration.(2) A treatment technique violation occurs whe…

When a treatment technique violation occurs, the purveyor:(1) Shall report to the department in accordance with:(a) WAC 246-290-666 for purveyors providing filtration or required to filter;(b) WAC 246-290-674 for purveyors installing filtration; or(c) WAC 246-290-696 for purveyor…

(1) The purveyor shall calculate T at peak hourly flow for each surface or GWI source.(2) For pipelines, the purveyor shall calculate T by dividing the internal volume of the pipe by the peak hourly flow rate through that pipe.(3) For all other system components used for inactiva…

(1) The purveyor shall ensure that only qualified persons conduct measurements for pH, temperature, turbidity, and residual disinfectant concentrations. In this section, qualified means:(a) A person certified under chapter 246-292 WAC;(b) An analyst, with experience conducting th…

(1) Purveyors using surface or GWI sources shall maintain accurate and complete operations records.(2) Operations records shall include, but not be limited to, the following as applicable:(a) Results of all monitoring conducted under Part 6 of chapter 246-290 WAC;(b) Quantity of …

(1) Until the department has made a source GWI determination, the purveyor shall monitor in accordance with the requirements for groundwater sources in WAC 246-290-300 or as directed by the department and provide follow-up in accordance with WAC 246-290-320.(2) The purveyor, afte…

(1) In addition to the requirements of Parts 1 through 5 of chapter 246-290 WAC, Subpart B of Part 6 of chapter 246-290 WAC applies to purveyors of systems using surface or GWI sources and providing filtration, including:(a) Systems with water treatment facilities that produced w…

(1) The purveyor shall treat all surface and GWI sources using one of the following filtration technologies unless another technology is acceptable to the department:(a) Conventional;(b) Direct;(c) Diatomaceous earth; or(d) Slow sand.(2) Purveyors not using one of the filtration …

(1) The purveyor shall operate filters so that maximum flow rates do not exceed those specified in Table 14 of this section. The purveyor may operate filters at higher flow rates, if the purveyor demonstrates to the department's satisfaction that filtration at the higher rate con…

(1) Turbidity performance requirements.(a) The turbidity level of representative filtered water samples must:(i) Comply with the performance standards in Table 15 of this section;(ii) Never exceed 5.0 NTU for any system using slow sand, diatomaceous earth;(iii) Never exceed 1.0 N…

(1) General requirements.(a) The purveyor shall provide continuous disinfection to ensure that filtration and disinfection together achieve, at all times the system serves water to the public, at least the following:(i) 99.9 percent (3-log) inactivation and removal of Giardia lam…

(1) Source coliform monitoring.(a) The purveyor shall ensure that source water samples of each surface or GWI source are:(i) Collected before the first point of disinfectant application and before coagulant chemical addition; and(ii) Analyzed for fecal coliform density in accorda…

(1) The purveyor shall notify the department, as soon as possible, but no later than twenty-four hours after the purveyor learns of the following events:(a) A waterborne disease outbreak potentially attributable to the water system occurs; (b) The turbidity of the combined filter…

(1) The purveyor shall, to the extent possible, exercise surveillance over conditions and activities in the watershed affecting source water quality. The purveyor shall develop and implement a department-approved watershed control program.(2) The purveyor shall include a current …

(1) The purveyor of an existing unfiltered system shall:(a) Install filtration within eighteen months after department notification; and(b) Be subject to the interim compliance requirements as determined by the department and in conformance with 40 C.F.R. 141.13 and WAC 246-290-6…

(1) Purveyors of existing unfiltered systems installing filtration shall provide interim disinfection treatment to:(a) Ensure compliance with the monthly coliform MCL under WAC 246-290-310; (b) Achieve inactivation levels of Giardia lamblia cysts on a daily basis each month the s…

(1) Monitoring. Unless directed otherwise by the department, the purveyor of an existing unfiltered system installing filtration shall:(a) Conduct interim monitoring in accordance with 40 C.F.R. 141.22; (b) Measure the residual disinfectant concentration within the distribution s…

(1) General.(a) The purveyor proposing to construct new water treatment facilities or to make additions to existing water treatment facilities for surface and GWI sources shall ensure that the facilities comply with the treatment, design, and reliability requirements of Part 6 of…

(1) The purveyor shall ensure that reliability features are included in all water treatment facilities used to treat surface or GWI sources.(2) Reliability features shall include but not be limited to:(a) Alarm devices to provide warning of treatment process failures including co…

(1) The purveyor using an unfiltered surface or GWI source shall comply with:(a) Subparts A and D of Part 6 of chapter 246-290 WAC; and(b) All other applicable sections of this chapter.(2) The purveyor purchasing water from a system using a surface or GWI source shall comply with…

(1) For a system not using the "limited alternative to filtration" option to remain unfiltered, the purveyor using a surface water or GWI source shall meet the source water quality and site-specific conditions under this section, as demonstrated through monitoring conducted in ac…

(1) For a system providing a limited alternative to filtration, the purveyor using a surface water or GWI source shall meet the source quality and site-specific conditions under this section.(2) Source water turbidity requirements.(a) The purveyor shall ensure that the turbidity …

(1) General requirements.(a) The purveyor without a limited alternative to filtration shall:(i) Provide continuous disinfection treatment to ensure at least 99.9 percent (3-log) inactivation of Giardia lamblia cysts and 99.99 percent (4-log) inactivation of viruses at all times t…

(1) Source coliform monitoring for systems without a limited alternative to filtration.(a) The purveyor shall ensure that source water samples of each surface or GWI source are representative and:(i) Collected before the first point of disinfectant application; and(ii) Analyzed f…

(1) The purveyor shall report to the department as soon as possible, but no later than twenty-four hours after the purveyor learns of any of the following events:(a) A waterborne disease outbreak potentially attributable to the water system occurs;(b) The turbidity of water deliv…

(1) The purveyor shall notify the water system users and the owner or operator of any consecutive water system served in accordance with 40 C.F.R. 141.201 through 208. Notice is to be provided when the system violates a National Primary Drinking Water Regulation and when any of t…

(1) Public notices required under WAC 246-290-71001(1) must contain the elements and standard language required under 40 C.F.R. 141.205 (a), (b), and (d) and be presented in accordance with 40 C.F.R. 141.205 (c), except that notification of the availability of results required pe…

(1) Purveyors must provide public notice as required under WAC 246-290-71001(1) according to Tier designation generally described in 40 C.F.R. 141.201. The form, manner, timing and frequency for each Tier of public notice, as defined in Table 2 of 40 C.F.R. 141.201 shall be in ac…

(1) Public notice required under WAC 246-290-71001(1) must contain any specific health effects language set forth in WAC 246-290-72400 in accordance with 40 C.F.R. 141.205 (d)(1) and other standard language in accordance with 40 C.F.R. 141.205 (d)(2) and (3), except that notifica…

(1) The purveyor of community or NTNC water systems required to monitor under 40 C.F.R. 141.40 shall notify the water system users of the availability of the results of monitoring for unregulated contaminants no later than 12 months after the monitoring results are known. The for…

(1) The purveyor shall provide public notice to the water system users when the department determines that a contaminant exceeds a SAL listed in WAC 246-290-315, Table 9.(2) The public notice must be in conformance with the requirements under WAC 246-290-71001 through 246-290-710…

(1) When circumstances dictate, the purveyor shall give a broader or more immediate notice to protect public health. The department may require the purveyor's notification by whatever means necessary.(2) When the state board of health grants a public water system a waiver, the pu…

This section expires on January 1, 2027. WAC 246-290-72001 through 246-290-72400 establishes minimum requirements for the content of annual reports that community water systems must deliver to their customers. These reports must contain information on the quality of the water del…