All public water systems that add chlorine for the purpose of continuous disinfection are required to monitor the residual disinfectant concentration as described in the chlorination requirements section below.

With the adoption of the Group A WAC changes in January 2017, detectable residual disinfectant concentration has been defined and must be at least 0.2 mg/L.

No more color wheel for source disinfection compliance. If your system is required to treat to CT6 or 4-log virus inactivation, you must measure free chlorine residual in accordance with an EPA-approved method. A color wheel can't be used to comply with these requirements. A digital colorimeter using an EPA approved method is allowed.

All public water systems that chlorinate are subject to the following violations.

Failure to submit your report by the 10th of the following month.

Failure to meet the required minimum residual at entry or throughout the distribution system.

Contact your regional office to receive a customized form including all requirements specific to your system, or you can download a form for your system using the links below.

Submit your monthly treatment reports by email, mail, or fax to your regional office by the tenth day of the following month.

16201 East Indiana Avenue, Suite 1500 Spokane Valley, WA 99216 509-329-2100 Fax: 509-329-2104 DOHDWChlorination@doh.wa.gov

PO Box 47823 Olympia, WA 98504-7823 360-236-3030 Fax: 360-236-3029 SW.Treatment.Reports@doh.wa.gov

For people with disabilities, Web documents in other formats are available on request. To submit a request, please contact us at civil.rights@doh.wa.gov.

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