Well Water Testing Requirements in Washington (WA)
Washington does not require ongoing private well testing. New wells must be tested for bacteria and nitrate. The Washington Department of Ecology manages well permits. The state offers Group B water system regulations for small shared wells. PFAS contamination has been found near military bases. The state has approximately 500,000 private wells.
Required Contaminant Tests in Washington
Washington requires testing for the following 2 contaminants for new wells:
Common Contaminants in Washington Well Water
Based on geological conditions, land use patterns, and historical testing data, these contaminants are commonly found in Washington private wells. Even if not required by law, testing for these contaminants is recommended.
Testing Requirements by City in Washington
Local testing requirements may vary from state-level regulations. Some counties and municipalities have stricter rules than the state minimum. Below are details for major cities in Washington.
| City | Testing Required | Notes |
|---|---|---|
| Seattle | No | King County; limited private wells in metro |
| Spokane | No | Spokane County; Spokane Valley-Rathdrum Prairie aquifer |
| Tacoma | No | Pierce County; some private wells |
| Olympia | No | State capital; Thurston County |
| Bellingham | No | Whatcom County; Nooksack River area |
Testing Recommendations for Washington Well Owners
- Even though your state does not require testing, the EPA recommends testing private well water annually for bacteria and nitrate.
- Arsenic is a known contaminant in your state. Test for arsenic at least once, even if not required.
- PFAS (forever chemicals) have been detected in your state. Consider testing for PFAS compounds.
- Nitrate contamination is common in your area. Test annually, especially if near agricultural land.
Understanding Washington's Well Water Regulations
Testing Frequency
Washington does not require ongoing testing of private well water. However, the EPA recommends all private well owners test annually for bacteria and nitrate, regardless of state requirements. Proactive testing is the only way to ensure your well water is safe.
New Well Requirements
Washington requires testing when a new well is constructed or an existing well is significantly modified. The required tests include bacteria (coliform/e. coli), nitrate, and the well must pass these tests before being put into service for drinking water. Well construction must comply with state standards and a permit is required before drilling.
State Laboratory and Testing Resources
Washington operates a state laboratory or participates in a state lab network that provides water testing services, often at subsidized rates below commercial laboratory prices. Contact your state health department or environmental agency for current pricing and sample submission procedures. Many county health departments also offer basic bacteria testing, sometimes at no cost. The average cost for a comprehensive well water test in Washington is approximately $200, though a basic bacteria and nitrate screen may cost significantly less.
How Washington Compares
Washington has a minimal level of well water testing regulation. Below are other states with similar regulatory approaches.
| State | Testing Required | Test at Sale | Required Tests | Avg. Cost |
|---|---|---|---|---|
| Washington (WA) | No | No | 2 | $200 |
| Alabama (AL) | No | No | 1 | $150 |
| Alaska (AK) | No | No | 2 | $200 |
| Arizona (AZ) | No | No | 2 | $175 |
| Arkansas (AR) | No | No | 1 | $125 |
| California (CA) | No | No | 2 | $250 |
Check Other States
Use our well water testing lookup tool to check requirements for any state, or browse all 50 states ranked by testing strictness. If you are moving to or buying property in Washington, understanding the testing requirements is an important part of your due diligence.