The Office of Drinking Water (overview)

Click here for Office of Drinking Water's main page - information for water systems.

Click here for Office of Drinking Water information for consumers.


Our mission is to protect the health of the people of Washington by ensuring safe and reliable drinking water. More than 6.2 million Washington residents get their drinking water from a Group A or Group B public water system. That's 85 percent of the state's population. About 725,000 Washington residents get their drinking water from individual private wells and are regulated by local health jurisdictions. Read more about private wells (PDF, DOH 331-349).

We regulate Group A public water systems under state law and a formal agreement with the U.S. Environmental Protection Agency (EPA) for carrying out the federal Safe Drinking Water Act, which establishes minimum standards for drinking water quality. Read more about the formal agreement with EPA.

Emergency response

Our highest priority is responding to actual or potential public health emergencies. Emergencies include water outages, water main breaks, water system distribution or water quality problems, earthquakes, floods, power outages, windstorms, vandalism, or terrorism. Contamination of drinking water supplies can come from bacteria, chemicals, or other sources. See emergency publications for consumers.

We work closely with the water system, the community, and the local health jurisdiction to get drinking water operations back to normal. Our technical staff is available to water systems 24 hours a day during an emergency.

Preventing problems

Our rules and programs rely on prevention as the first line of defense, with a goal of avoiding potentially health-threatening and costly problems.

Water system inspections (sanitary surveys) look at all aspects of water system operations, including water sources, pumps, storage tanks, treatment units, filtration plants, water monitoring records, and technical, financial, and managerial capacity. Waterworks operator certification, training, and continuing education programs ensure that the people operating public water systems are qualified and capable.

Technical assistance programs, grant and loan programs, and construction plan reviews help us ensure proper design and operation of water systems. Ongoing source and distribution monitoring helps water systems detect contamination and resolve problems quickly. Our source water protection program focuses water utilities on maintaining, safeguarding, and improving the quality and quantity of their source water to prevent contamination and the loss of supply.

Our planning program helps water systems evaluate their overall technical, financial, and managerial capacity, identify current and future challenges, and establish policies, practices, and financial strategies to address them. Our water use efficiency program helps water systems protect against temporary water service interruptions during peak usage, long-term or repeated water disruptions due to limited water supply, and contamination of the water supply due to leaky pipes. Our enforcement strategies help to ensure that water systems address risks in a timely manner.

Keeping customers informed

Public water systems must test drinking water for contaminants that can cause health problems. They also must provide their customers with a yearly Consumer Confidence Report that includes information about the quality of their drinking water. For acute health risks, such as bacterial contamination, water systems must notify their customers within 24 hours. For more information

Toll-Free Numbers:

Main Office 800-521-0323

Operator Certification Program 360-236-3155

After-Hours Emergency Hotline (for water systems and operators) 877-481-4901

Regional Offices

Our regional offices provide technical assistance to water systems and local health jurisdictions, implement the state's drinking water programs, monitor water quality, conduct sanitary surveys and special purpose investigations, and review and approve water system plans. View local health jurisdictions map.

Eastern Region: Spokane Valley 509-329-2100

Serving Adams, Asotin, Benton, Chelan, Columbia, Douglas, Ferry, Franklin, Garfield, Grant, Kittitas, Klickitat, Lincoln, Okanogan, Pend Oreille, Spokane, Stevens, Walla Walla, Whitman, and Yakima counties.

Northwest Region: Kent 253-395-6750

Island, King, Pierce, San Juan, Skagit, Snohomish, and Whatcom counties.

Southwest Region: Tumwater 360-236-3030

Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Kitsap, Lewis, Mason, Pacific, Skamania, Thurston, and Wahkiakum counties.