Oregon Water Quality
Drinking water data for all 36 counties.
Avg Water Score
44.6
State Grade
D
Counties with Data
36
of 36 total
All Oregon Counties
| County | Water Score |
|---|---|
| Gilliam County | 86.0 |
| Harney County | 86.0 |
| Jefferson County | 86.0 |
| Sherman County | 86.0 |
| Union County | 86.0 |
| Wallowa County | 86.0 |
| Wheeler County | 86.0 |
| Washington County | 67.7 |
| Multnomah County | 66.8 |
| Deschutes County | 60.1 |
| Linn County | 53.8 |
| Marion County | 50.4 |
| Klamath County | 50.1 |
| Hood River County | 49.3 |
| Umatilla County | 45.9 |
| Polk County | 45.5 |
| Lake County | 42.7 |
| Clackamas County | 37.6 |
| Crook County | 35.0 |
| Yamhill County | 34.0 |
| Morrow County | 33.9 |
| Clatsop County | 32.7 |
| Grant County | 29.4 |
| Lane County | 29.0 |
| Douglas County | 28.5 |
| Baker County | 28.4 |
| Lincoln County | 27.8 |
| Tillamook County | 27.3 |
| Benton County | 21.6 |
| Jackson County | 19.6 |
| Josephine County | 16.9 |
| Wasco County | 15.9 |
| Coos County | 14.0 |
| Columbia County | 13.9 |
| Curry County | 13.9 |
| Malheur County | 11.4 |
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Frequently Asked Questions
Which county in Oregon has the best water quality?
Gilliam County has the highest water quality score in Oregon at 86.0/100 (Grade: A), based on EPA SDWIS data.
Which county in Oregon has the most water violations?
Malheur County has among the lowest water quality scores in Oregon at 11.4/100. See the individual county page for detailed violation history.
Is the tap water safe to drink in Oregon?
Oregon has an average water quality score of 44.6/100 based on EPA Safe Drinking Water Act compliance data. Individual county scores vary — check your specific county's page for detailed information.
What contaminants are found in Oregon water supplies?
Drinking water quality varies by county and water system. The EPA Safe Drinking Water Information System (SDWIS) tracks violations for contaminants like lead, nitrates, bacteria, and disinfection byproducts. See individual county pages for specific contaminant and violation history.
Data Source
Water quality data sourced from the EPA Safe Drinking Water Information System (SDWIS) via the ECHO enforcement database. Scores reflect compliance history and health-based violation counts.
Disclaimer: This data is informational only. It is not health, legal, or professional advice. For concerns about your specific water supply, contact your local water utility.