Washington Water Quality
According to EPA Safe Drinking Water Information System (SDWIS), Washington has 2,410 active community water systems in this extract. PlainEnviro's health-based slice lists 2,879 violation records across 50 systems with at least one such row. These are historical EPA registry counts, not a statewide drinkability score.
Health-based violation records for 2,410 community water systems in Washington. Source: EPA Safe Drinking Water Information System (SDWIS).
Water Systems with Most Health-Based Records
| # | Water System | Health-Based Records | Health |
|---|---|---|---|
| 1 | ORIENT WATER COMPANY Republic | 134 | Yes |
| 2 | DELTA WATER ASSOCIATION Lynden | 126 | Yes |
| 3 | WALLA WALLA WATER DIVISION Walla Walla | 105 | Yes |
| 4 | SUNRISE ESTATES WATER SYSTEM Moses Lake | 85 | Yes |
| 5 | COXVILLE WATER ASSN #1 Benton City | 81 | Yes |
| 6 | RED GATE MOBILE HOME PARK Port Orchard | 78 | Yes |
| 7 | SPRING POINT HOMEOWNERS ASSOCIATION Deer Harbor | 73 | Yes |
| 8 | MARTHA BOARDMAN Wellpinit | 67 | Yes |
| 9 | FORD-NEWHOUSE LANE Wellpinit | 59 | Yes |
| 10 | KAPOWSIN WATER DISTRICT Puyallup | 48 | Yes |
| 11 | MCNEIL ISLAND WATER Tumwater | 47 | Yes |
| 12 | MAKAH NEAH BAY Neah Bay | 45 | Yes |
| 13 | DEVRIES ROAD COMMUNITY ASSN Coupeville | 45 | Yes |
| 14 | COLUMBIA CREST ESTATES Napavine | 44 | Yes |
| 15 | CAPE SAN JUAN WATER DISTRICT Friday Harbor | 42 | Yes |
| 16 | GOLF MHP Seattle | 41 | Yes |
| 17 | HOT SPRINGS COURT Seattle | 40 | Yes |
| 18 | ARROWHEAD BEACH COOP WATER ASSOC Mt Vernon | 37 | Yes |
| 19 | BC WATER CO Kennewick | 36 | Yes |
| 20 | BONNIE VIEW WATER Oak Harbor | 34 | Yes |
| 21 | CALMOR COVE CLUB Lynden | 34 | Yes |
| 22 | RIDGEVIEW ESTATES COMMUNITY ASSN. Freeland | 34 | Yes |
| 23 | PENN COVE WATER AND SEWER DISTRICT Oak Harbor | 32 | Yes |
| 24 | SARATOGA WATER DISTRICT Coupeville | 31 | Yes |
| 25 | BEVERLY BEACH IMPROVEMENT CLUB Mt Vernon | 30 | Yes |
| 26 | PARKER SPRING ACRES WATER ASSOC Moses Lake | 30 | Yes |
| 27 | SUNDANCE IMPROVEMENT ASSOCIATION Kennewick | 29 | Yes |
| 28 | CAMPBELLS GLEN Clinton | 28 | Yes |
| 29 | SIERRA COUNTRY CLUB Coupeville | 26 | Yes |
| 30 | RIVER VILLAGE MHP Seattle | 25 | Yes |
| 31 | TOWNSHIP 29 WATER ASSOCIATION Mt Vernon | 24 | Yes |
| 32 | COUNTRY CLUB ESTATES 521 Olympia | 24 | Yes |
| 33 | BADGER MOUNTAIN IRRIGATION DISTRICT Kennewick | 24 | Yes |
| 34 | TAMOSHAN Olympia | 23 | Yes |
| 35 | 5 CEDARS Deming | 22 | Yes |
| 36 | BEACHWOOD WATER COMPANY Coupeville | 22 | Yes |
| 37 | FAIRWAY NUMBER THREE WATER Friday Harbor | 22 | Yes |
| 38 | LISECC Lummi Island | 22 | Yes |
| 39 | GREATER BAR WATER DISTRICT Bridgeport | 19 | Yes |
| 40 | CAMANO SUNSET WATER SYSTEM Mount Vernon | 19 | Yes |
| 41 | GOLDEN VALLEY WATER ASSN Quincy | 19 | Yes |
| 42 | ROLLING HILLS-GLENCAIRN Oak Harbor | 19 | Yes |
| 43 | OLYMPIC PARK TRAILER COURT Olympia | 18 | Yes |
| 44 | TWO RIVERS RESORT Wellpinit | 18 | Yes |
| 45 | EASTGATE Coupeville | 18 | Yes |
| 46 | FALL CITY WATER DIST.(SPRING HILL) Fall City | 18 | Yes |
| 47 | SURFSIDE HOMEOWNERS Ocean Park | 17 | Yes |
| 48 | E.L.C. WATER SYSTEM Eastsound | 16 | Yes |
| 49 | AgriNorthwest Riverbend Pasco | 16 | Yes |
| 50 | HIWAY TRAILER COURT Port Orchard | 16 | Yes |
Most Common Contaminants in Washington
| Contaminant | Violations | Systems Affected |
|---|---|---|
| Nitrate | 627 | 43 |
| TTHM | 471 | 38 |
| Arsenic | 436 | 33 |
| Surface Water Treatment Rule | 407 | 37 |
| Groundwater Rule | 287 | 45 |
| Total Haloacetic Acids (HAA5) | 228 | 17 |
| Revised Total Coliform Rule | 157 | 80 |
| Coliform (TCR) | 60 | 18 |
| Fluoride | 52 | 3 |
| Lead and Copper Rule | 45 | 26 |
| LEAD AND COPPER RULE REVISIONS | 31 | 28 |
| Long Term 2 Enhanced Surface Water Treatment Rule | 30 | 5 |
| Interim Enhanced Surface Water Treatment Rule | 23 | 5 |
| Combined Uranium | 12 | 2 |
| CARBON, TOTAL | 10 | 1 |
Cities with Water Quality Issues
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About This Data
Water quality data is from the EPA Safe Drinking Water Information System (SDWIS). Health-based violations include Maximum Contaminant Level (MCL) and Treatment Technique (TT) violations. Only community water systems (CWS) in Washington are included.
Source: U.S. Environmental Protection Agency, SDWIS Federal Reporting Services
Read our methodology - how this data is sourced, computed, and verified.