Systems reaching a study comparison level
8.3%19 of 229 active community water systems with complete monitoring
All 229 systems had complete monitoring. 19 reached at least one study comparison level; 210 did not. “Study comparison level” means the dated EPA technical cutoff used in this January 2026 research release. It does not determine household exposure, health risk, or current legal compliance.
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ZIP codes are used only to route visitors to public water systems that reported serving them. Confirm the actual provider using a water bill or utility record.
Compound summary
System counts in Washington
Each count shows how many included water systems reached the named study level.
| Study comparison | Systems reaching level | Water systems included | Percent |
|---|---|---|---|
| PFOA: study level 4.05 ppt (April 2024 EPA level: 4 ppt) | 4 | 229 | 1.7% |
| PFOS: study level 4.05 ppt (April 2024 EPA level: 4 ppt) | 18 | 229 | 7.9% |
| PFHxS: study level 15 ppt (April 2024 EPA level: 10 ppt) | 3 | 229 | 1.3% |
| PFNA: study level 15 ppt (April 2024 EPA level: 10 ppt) | 0 | 229 | 0.0% |
| HFPO-DA: study level 15 ppt (April 2024 EPA level: 10 ppt) | 0 | 229 | 0.0% |
| Hazard Index: study level 1.5 with at least two detected components (April 2024 EPA level: 1) | 3 | 229 | 1.3% |
System directory
Community water systems with complete monitoring
Each PWSID appears once, preventing double counting across ZIP associations.
| Public water system | PWSID | Population served | Primary source | Sampling locations | Study comparison |
|---|---|---|---|---|---|
| ABERDEEN CITY OF | WA5300050 | 22,867 | Surface water | 1 | Below the study levels |
| AIRWAY HEIGHTS CITY OF | WA5300650 | 9,489 | Ground water | 2 | Below the study levels |
| ALDERWOOD WATER DISTRICT | WA5301300 | 245,715 | Surface water purchased | 1 | Below the study levels |
| ANACORTES CITY OF | WA5302200 | 25,109 | Surface water | 1 | Below the study levels |
| ARLINGTON WATER DEPT | WA5302950 | 29,508 | Surface water purchased | 3 | Below the study levels |
| ARTONDALE WATER SYSTEM | WA5303160 | 5,828 | Ground water | 10 | Below the study levels |
| Auburn City of | WA5303350 | 107,655 | Ground water | 6 | Below the study levels |
| BAINBRIDGE ISLAND CITY OF | WA5397650 | 13,491 | Ground water | 4 | Below the study levels |
| BAYSHORE | WA5304900 | 130 | Ground water | 1 | Below the study levels |
| BEACON HILL WATER & SEWER DISTRICT | WA5315650 | 11,969 | Ground water purchased | 1 | Below the study levels |
| BELLEVUE CITY OF | WA5305575 | 321,349 | Surface water purchased | 2 | Below the study levels |
| BELLINGHAM-WATER DIVISION CITY OF | WA5305600 | 141,127 | Surface water | 1 | Below the study levels |
| BENTON CITY WATER | WA5305800 | 5,626 | Ground water | 3 | Reached a study level |
| BIRCH BAY WATER & SEWER DISTRICT | WA5395904 | 9,046 | Ground water purchased | 3 | Below the study levels |
| BLAINE CITY OF | WA5307300 | 6,319 | Ground water | 3 | Below the study levels |
| BONNEY LAKE WATER DEPARTMENT CITY | WA5307650 | 43,371 | Surface water purchased | 5 | Below the study levels |
| BOTHELL WATER CITY OF | WA5307900 | 33,643 | Surface water purchased | 1 | Below the study levels |
| BREMERTON CITY OF | WA5308200 | 72,951 | Surface water | 7 | Below the study levels |
| BUCKLEY WATER | WA5309000 | 7,842 | Surface water purchased | 7 | Below the study levels |
| CAMAS MUNICIPAL WATER SEWER SYSTEM | WA5310800 | 31,794 | Ground water | 5 | Reached a study level |
| CASTLE ROCK MUNICIPAL WATER | WA5311800 | 4,367 | Surface water | 5 | Below the study levels |
| CEDAR GROVE MOBILE PARK | WA5336836 | 40 | Ground water | 1 | Below the study levels |
| CEDAR RIVER WATER & SEWER DISTRICT | WA5341800 | 28,671 | Surface water purchased | 2 | Below the study levels |
| CENTRALIA PUBLIC WORKS - WATER | WA5312200 | 28,164 | Ground water | 3 | Reached a study level |
| CHELAN CO PUD 1 | WA5312284 | 16,190 | Ground water purchased | 1 | Below the study levels |
| CHELAN WATER DEPT CITY OF | WA5312300 | 9,425 | Surface water | 1 | Below the study levels |
| CHENEY CITY OF | WA5312400 | 16,954 | Ground water | 5 | Below the study levels |
| CLARK PUBLIC UTILITIES | WA5313333 | 153,526 | Ground water | 10 | Reached a study level |
| COAL CREEK UTILITY DISTRICT | WA5341750 | 15,989 | Surface water purchased | 1 | Below the study levels |
| COLFAX WATER DEPARTMENT CITY OF | WA5314000 | 3,507 | Ground water | 3 | Below the study levels |
| COLLEGE PLACE WATER DEPT | WA5314050 | 8,147 | Ground water | 5 | Below the study levels |
| COLVILLE WATER DEPARTMENT | WA5314200 | 4,945 | Ground water | 2 | Below the study levels |
| CONNELL CITY OF | WA5314600 | 5,150 | Ground water | 3 | Below the study levels |
| CONSOLIDATED IRRIG DIST 19 SYSTEM 1 | WA5310220 | 9,434 | Ground water | 3 | Below the study levels |
| CONSOLIDATED IRRIG DIST 19 SYSTEM 2 | WA5310221 | 21,220 | Ground water | 4 | Below the study levels |
| COUPEVILLE TOWN OF | WA5315550 | 4,142 | Ground water | 1 | Reached a study level |
| COVINGTON WATER DISTRICT | WA5341650 | 56,172 | Surface water purchased | 3 | Reached a study level |
| CRESCENT WATER ASSN | WA5316020 | 2,360 | Surface water | 1 | Below the study levels |
| CROSS VALLEY WATER DISTRICT | WA5316270 | 24,695 | Surface water purchased | 6 | Below the study levels |
| CRYSTAL MOUNTAIN INC | WA5316400 | 4,154 | Surface water | 1 | Below the study levels |
| Columbia Valley Water District | WA5366110 | 2,648 | Ground water | 3 | Below the study levels |
| DEER PARK CITY OF | WA5318500 | 5,435 | Ground water | 8 | Below the study levels |
| DUNGENESS MEADOWS | WA5320445 | 488 | Ground water | 3 | Below the study levels |
| DUPONT WATER SYSTEM CITY OF | WA5320500 | 13,141 | Ground water | 2 | Below the study levels |
| DUVALL CITY OF | WA5320750 | 11,050 | Surface water purchased | 1 | Below the study levels |
| EAST SPOKANE WATER DIST 1 | WA5321650 | 4,285 | Ground water | 4 | Below the study levels |
| EAST WENATCHEE WATER DISTRICT | WA5321800 | 26,519 | Ground water purchased | 1 | Below the study levels |
| EASTERN WASHINGTON UNIVERSITY | WA5321900 | 17,108 | Ground water | 1 | Below the study levels |
| EASTSOUND WATER USERS ASSOCIATION | WA5322170 | 3,711 | Surface water | 4 | Below the study levels |
| EATONVILLE WATER DEPT | WA5322300 | 3,945 | Surface water | 1 | Below the study levels |
| EDMONDS CITY OF | WA5322500 | 34,065 | Surface water purchased | 1 | Below the study levels |
| ELLENSBURG WATER DEPT | WA5322950 | 20,900 | Ground water | 8 | Below the study levels |
| EMERALD LAKE | WA5323294 | 331 | Ground water | 1 | Below the study levels |
| ENUMCLAW WATER DEPARTMENT | WA5323600 | 23,276 | Ground water | 4 | Below the study levels |
| EPHRATA WATER DEPARTMENT | WA5323650 | 8,718 | Ground water | 5 | Below the study levels |
| EVERETT PUBLIC WORKS DEPT. CITY OF | WA5324050 | 215,774 | Surface water | 2 | Below the study levels |
| EVERSON CITY OF | WA5324200 | 3,893 | Ground water | 1 | Below the study levels |
| FAIRCHILD AIR FORCE BASE | WA5324350 | 9,544 | Ground water | 2 | Reached a study level |
| FERNDALE WA | WA5324850 | 19,305 | Ground water | 1 | Below the study levels |
| FIRCREST CITY OF | WA5325150 | 7,927 | Ground water | 4 | Below the study levels |
| FIRGROVE MUTUAL INC | WA5325200 | 36,168 | Surface water purchased | 13 | Below the study levels |
| FORKS MUNICIPAL WATER DEPT | WA5326000 | 3,468 | Ground water | 2 | Below the study levels |
| FRIDAY HARBOR TOWN OF | WA5326595 | 3,543 | Surface water | 1 | Below the study levels |
| FRUITLAND MUTUAL WATER COMPANY | WA5326800 | 15,313 | Ground water | 4 | Below the study levels |
| GIG HARBOR WATER DEPT | WA5327600 | 16,510 | Ground water | 6 | Below the study levels |
| GOLD BAR CITY OF | WA5328300 | 2,745 | Ground water | 2 | Below the study levels |
| GOLDENDALE CITY OF | WA5328450 | 4,314 | Ground water | 2 | Below the study levels |
| GRANDVIEW CITY OF | WA5328970 | 11,010 | Ground water | 9 | Below the study levels |
| GRANGER WATER DEPARTMENT | WA5329000 | 3,993 | Ground water | 1 | Below the study levels |
| GRANITE FALLS CITY OF | WA5329050 | 5,349 | Surface water purchased | 1 | Below the study levels |
| GRAYS HARBOR CO WATER DIST 2 | WA5329250 | 5,112 | Ground water | 1 | Below the study levels |
| HEIGHTS WATER | WA5332300 | 2,051 | Ground water | 1 | Below the study levels |
| HI VALLEY VIEW | WA5300431 | 67 | Ground water | 1 | Below the study levels |
| HIGHLINE WATER DISTRICT | WA5340650 | 100,170 | Surface water purchased | 3 | Below the study levels |
| HOQUIAM WATER DEPARTMENT | WA5334350 | 11,456 | Surface water | 1 | Below the study levels |
| HORIZONS WEST | WA5334375 | 3,454 | Ground water | 6 | Below the study levels |
| IRVIN WATER DISTRICT #6 | WA5336050 | 4,150 | Ground water | 4 | Below the study levels |
| ISSAQUAH WATER SYSTEM | WA5336350 | 43,584 | Surface water purchased | 4 | Below the study levels |
| JBLM Lewis | WA5326050 | 35,414 | Ground water | 6 | Reached a study level |
| JBLM McChord Field | WA5352200 | 7,290 | Ground water | 7 | Reached a study level |
| KALAMA CITY OF | WA5337550 | 8,020 | Groundwater under influence of surface water | 1 | Below the study levels |
| KELSO CITY OF | WA5338000 | 15,775 | Groundwater under influence of surface water | 1 | Below the study levels |
| KENNEWICK CITY OF | WA5338100 | 118,164 | Surface water | 2 | Reached a study level |
| KENT WATER DEPARTMENT | WA5338150 | 166,421 | Surface water purchased | 6 | Below the study levels |
| KING COUNTY WATER DISTRICT #125 | WA5341998 | 21,904 | Surface water purchased | 1 | Below the study levels |
| KING COUNTY WATER DISTRICT #20 | WA5338950 | 48,469 | Surface water purchased | 1 | Below the study levels |
| KING COUNTY WATER DISTRICT #49 | WA5339800 | 23,492 | Surface water purchased | 1 | Below the study levels |
| KING COUNTY WATER DISTRICT #54 | WA5339950 | 5,373 | Surface water purchased | 1 | Below the study levels |
| KING COUNTY WATER DISTRICT 119 | WA5341985 | 3,800 | Surface water purchased | 1 | Below the study levels |
| KING COUNTY WATER DISTRICT NO 90 | WA5341150 | 20,100 | Surface water purchased | 2 | Below the study levels |
| KIRKLAND CITY OF | WA5342250 | 69,243 | Surface water purchased | 1 | Below the study levels |
| LACEY WATER DEPARTMENT | WA5343500 | 105,178 | Ground water | 12 | Below the study levels |
| LAKE CHELAN RECLAMATION DISTRICT | WA5343783 | 6,798 | Surface water | 1 | Below the study levels |
| LAKE CUSHMAN SYSTEM 5 | WA5303529 | 3,675 | Ground water | 7 | Below the study levels |
| LAKE FOREST PARK WATER DISTRICT | WA5340950 | 3,171 | Ground water | 3 | Below the study levels |
| LAKEHAVEN WATER AND SEWER DISTRICT | WA5341997 | 148,809 | Surface water purchased | 16 | Below the study levels |
| LAKEWOOD WATER DISTRICT | WA5345550 | 82,425 | Ground water | 5 | Reached a study level |
| LIBERTY LAKE SEWER & WATER DISTRICT | WA5347150 | 14,500 | Ground water | 4 | Below the study levels |
| LONG BEACH WATER DEPARTMENT | WA5348000 | 4,628 | Surface water | 1 | Below the study levels |
| LONGVIEW WATER DEPARTMENT | WA5348100 | 57,617 | Ground water | 1 | Below the study levels |
| LOST LAKE PROPERTY OWNERS ASSN | WA5348345 | 736 | Ground water | 1 | Below the study levels |
| LUMMI TRIBAL WATER DISTRICT | 105300002 | 3,699 | Surface water purchased | 7 | Below the study levels |
| LYNDEN WATER DEPARTMENT | WA5349150 | 20,062 | Surface water | 1 | Below the study levels |
| LYNNWOOD CITY OF | WA5349270 | 68,204 | Surface water purchased | 1 | Below the study levels |
| Lake Meridian Water District | WA5341900 | 24,231 | Surface water purchased | 5 | Below the study levels |
| MANCHESTER WATER DISTRICT | WA5350700 | 10,475 | Ground water | 8 | Below the study levels |
| MARYSVILLE UTILITIES | WA5351900 | 88,582 | Surface water purchased | 5 | Below the study levels |
| MCCORMICK WOODS | WA5340529 | 2,760 | Surface water purchased | 2 | Below the study levels |
| MEDICAL LAKE CITY OF | WA5353400 | 4,982 | Ground water | 2 | Below the study levels |
| MERCER ISLAND CITY OF | WA5353640 | 31,057 | Surface water purchased | 1 | Below the study levels |
| MILTON CITY OF | WA5354950 | 8,078 | Ground water | 2 | Below the study levels |
| MONROE WATER SYSTEM, WA | WA5355820 | 23,467 | Surface water purchased | 1 | Below the study levels |
| MONTESANO CITY OF | WA5356000 | 6,204 | Ground water | 2 | Below the study levels |
| MOSES LAKE CITY OF | WA5356300 | 32,428 | Ground water | 18 | Reached a study level |
| MOUNTAIN VIEW-EDGEWOOD WATER CO | WA5356820 | 9,680 | Ground water | 6 | Below the study levels |
| MOUNTLAKE TERRACE CITY OF | WA5357250 | 26,402 | Surface water purchased | 1 | Below the study levels |
| MOXEE WATER DEPARTMENT | WA5357300 | 5,599 | Ground water | 3 | Below the study levels |
| MT. VISTA - DUNGENESS GOLF COURSE | 105388889 | 517 | Ground water | 2 | Below the study levels |
| Mattawa City of | WA5352000 | 5,370 | Ground water | 1 | Below the study levels |
| Mukilteo Water & Wastewater Distr | WA5357550 | 31,437 | Surface water purchased | 3 | Below the study levels |
| NACHES TOWN OF | WA5358100 | 3,512 | Ground water | 2 | Below the study levels |
| NAVAL AIR STATION/WHIDBEY ISLAND | WA5303420 | 16,595 | Surface water purchased | 1 | Below the study levels |
| NAVAL BASE KITSAP AT BANGOR | WA5302714 | 16,828 | Ground water | 2 | Below the study levels |
| NAVAL BASE KITSAP AT BREMERTON | WA5303468 | 11,792 | Surface water purchased | 1 | Below the study levels |
| NE SAMMAMISH SEWER & WATER DISTRICT | WA5375265 | 9,702 | Ground water | 2 | Below the study levels |
| NOB HILL WATER ASSOCIATION | WA5359700 | 38,050 | Ground water | 5 | Below the study levels |
| NORTH BAINBRIDGE WATER CO | WA5359994 | 5,490 | Ground water | 1 | Below the study levels |
| NORTH BEACH WATER | WA5363000 | 8,093 | Ground water | 2 | Below the study levels |
| NORTH BEND, CITY OF | WA5360100 | 8,710 | Ground water | 2 | Below the study levels |
| NORTH PENINSULA | WA5305122 | 16,449 | Ground water | 6 | Below the study levels |
| NORTH PERRY AVE WATER DISTRICT | WA5360950 | 24,402 | Ground water | 9 | Below the study levels |
| NORTHSHORE UTILITY DISTRICT | WA5340800 | 99,789 | Surface water purchased | 1 | Below the study levels |
| North City Water District | WA5339600 | 32,847 | Surface water purchased | 1 | Below the study levels |
| OAK HARBOR CITY OF | WA5362650 | 23,675 | Surface water purchased | 1 | Below the study levels |
| OCEAN SHORES WATER DEPT | WA5363008 | 9,347 | Ground water | 1 | Below the study levels |
| OLYMPIA CITY OF | WA5363450 | 126,966 | Ground water | 6 | Below the study levels |
| OLYMPIC VIEW WATER & SEWER DISTRICT | WA5363600 | 17,784 | Surface water | 2 | Below the study levels |
| OMAK CITY OF | WA5363750 | 4,940 | Ground water | 3 | Below the study levels |
| ORCHARD AVENUE IRRIGATION DIST 6 | WA5364000 | 4,330 | Ground water | 2 | Below the study levels |
| ORTING CITY OF | WA5364500 | 10,332 | Ground water | 5 | Below the study levels |
| OTHELLO WATER DEPARTMENT | WA5364850 | 8,755 | Ground water | 7 | Below the study levels |
| PARKLAND LIGHT & WATER COMPANY | WA5366200 | 33,775 | Ground water | 5 | Reached a study level |
| PARKVIEW TERRACE | WA5366215 | 3,730 | Ground water | 5 | Below the study levels |
| PASADENA PARK IRR DIST 17 | WA5366300 | 6,269 | Ground water | 4 | Below the study levels |
| PASCO WATER DEPARTMENT | WA5366400 | 115,102 | Surface water | 2 | Below the study levels |
| PATTISON | WA5366578 | 4,643 | Ground water | 7 | Below the study levels |
| PEACOCK HILL | WA5366637 | 7,401 | Ground water | 26 | Below the study levels |
| POINT EVANS | WA5368065 | 5,211 | Ground water | 8 | Below the study levels |
| PORT ANGELES CITY OF | WA5368550 | 28,067 | Surface water | 1 | Below the study levels |
| PORT ANGELES COMPOSITE | WA5343296 | 8,872 | Surface water | 5 | Below the study levels |
| PORT TOWNSEND CITY OF | WA5369000 | 17,053 | Surface water | 1 | Below the study levels |
| POULSBO CITY OF | WA5369150 | 18,400 | Ground water | 6 | Below the study levels |
| PROSSER CITY OF | WA5369750 | 12,070 | Ground water | 1 | Below the study levels |
| PULLMAN WATER DEPARTMENT CITY OF | WA5369880 | 31,315 | Ground water | 5 | Below the study levels |
| PUYALLUP CITY OF | WA5370050 | 94,520 | Surface water purchased | 7 | Below the study levels |
| QUIMPER | WA5305783 | 14,548 | Ground water | 8 | Below the study levels |
| QUINCY WATER DEPARTMENT CITY OF | WA5370450 | 8,415 | Ground water | 5 | Below the study levels |
| QUISTORFF | WA5370550 | 1,113 | Ground water | 4 | Reached a study level |
| REDMOND WATER SYSTEM CITY OF | WA5371650 | 163,335 | Surface water purchased | 4 | Below the study levels |
| RENTON CITY OF | WA5371850 | 108,091 | Ground water | 3 | Below the study levels |
| RICHLAND CITY OF | WA5372250 | 106,499 | Surface water | 4 | Below the study levels |
| RIDGEFIELD PUBLIC WORKS | WA5372400 | 21,225 | Ground water | 6 | Below the study levels |
| Raymond Water Department | WA5371500 | 4,620 | Surface water | 1 | Below the study levels |
| SALLAL WATER ASSOCIATION INC | WA5375560 | 6,600 | Ground water | 4 | Below the study levels |
| SAMMAMISH PLATEAU WATER & SEWER | WA5340900 | 79,362 | Surface water purchased | 7 | Reached a study level |
| SEABECK | WA5303134 | 610 | Ground water | 1 | Below the study levels |
| SEASCAPE WATER ASSOCIATION | WA5307095 | 28 | Ground water | 1 | Below the study levels |
| SEATTLE PUBLIC UTILITIES | WA5377050 | 1,161,961 | Surface water | 2 | Below the study levels |
| SELAH CITY OF | WA5377400 | 9,331 | Ground water | 3 | Below the study levels |
| SEQUIM CITY OF | WA5377620 | 14,293 | Ground water | 3 | Below the study levels |
| SEVEN LAKES WATER ASSOCIATION | WA5377660 | 5,823 | Ground water | 4 | Below the study levels |
| SHELTER BAY COMMUNITY INC | WA5378155 | 2,212 | Surface water purchased | 1 | Below the study levels |
| SHELTON CITY OF | WA5378170 | 15,089 | Ground water | 3 | Below the study levels |
| SHOALWATER BAY | 105300019 | 898 | Ground water | 1 | Below the study levels |
| SILVER LAKE WATER & SEWER DISTRICT | WA5379250 | 65,033 | Surface water purchased | 1 | Below the study levels |
| SILVERDALE WATER DIST 16 | WA5379300 | 35,163 | Ground water | 10 | Below the study levels |
| SKAGIT COUNTY PUD 1 JUDY RES | WA5379500 | 111,415 | Surface water | 1 | Below the study levels |
| SKYWAY WATER & SEWER | WA5338800 | 12,036 | Surface water purchased | 3 | Below the study levels |
| SNO PUD 1 - LAKE STEVENS | WA5380907 | 67,710 | Surface water purchased | 2 | Below the study levels |
| SNOHOMISH CITY OF | WA5380915 | 16,367 | Surface water purchased | 2 | Below the study levels |
| SNOQUALMIE PASS UTILITY DISTRICT | WA5381048 | 5,832 | Ground water | 1 | Below the study levels |
| SNOQUALMIE WATER | WA5381080 | 20,222 | Ground water | 2 | Below the study levels |
| SOOS CREEK WATER & SEWER DISTRICT | WA5340100 | 74,172 | Surface water purchased | 1 | Below the study levels |
| SOUTHWOOD WATER SYSTEM | WA5382844 | 64,155 | Surface water purchased | 26 | Reached a study level |
| SPANAWAY WATER COMPANY | WA5382850 | 34,506 | Ground water | 10 | Reached a study level |
| SPO CO WATER DIST 3 SYS 2 | WA5393351 | 19,035 | Ground water | 5 | Below the study levels |
| SPO CO WATER DIST 3 SYS 3 | WA5393353 | 3,768 | Ground water | 2 | Below the study levels |
| SPO CO WATER DIST 3 SYS 4 | WA5393354 | 6,233 | Ground water | 4 | Below the study levels |
| SPOKANE CITY OF | WA5383100 | 346,138 | Ground water | 6 | Below the study levels |
| STANWOOD WATER DEPT CITY OF | WA5383650 | 17,586 | Ground water | 2 | Below the study levels |
| STEILACOOM TOWN OF | WA5384000 | 8,545 | Ground water | 1 | Below the study levels |
| STEVENS CO PUD - SUNCREST | WA5385202 | 7,484 | Ground water | 8 | Below the study levels |
| STEVENS CO PUD - VALLEY | WA5305520 | 550 | Ground water | 2 | Below the study levels |
| SULTAN WATER DEPARTMENT | WA5384770 | 8,424 | Surface water | 2 | Below the study levels |
| SUMMIT WATER & SUPPLY CO | WA5385050 | 19,125 | Ground water | 7 | Below the study levels |
| SUMNER CITY OF | WA5385120 | 16,438 | Ground water | 7 | Below the study levels |
| SUQUAMISH | WA5386400 | 4,203 | Ground water | 4 | Below the study levels |
| Snake River Housing Water System | WA5300710 | 3,036 | Ground water | 2 | Below the study levels |
| TACOMA WATER DIVISION CITY OF | WA5386800 | 446,170 | Surface water | 3 | Below the study levels |
| TOPPENISH WATER DEPARTMENT | WA5388850 | 8,950 | Ground water | 5 | Below the study levels |
| TRENTWOOD IRRIGATION DISTRICT 3 | WA5389250 | 4,228 | Ground water | 4 | Reached a study level |
| TUKWILA WATER DEPARTMENT | WA5389500 | 36,298 | Surface water purchased | 1 | Below the study levels |
| TULALIP BAY WATER DIST #1 | 105300003 | 5,968 | Surface water purchased | 1 | Below the study levels |
| TUMWATER CITY OF | WA5389700 | 51,802 | Ground water | 5 | Below the study levels |
| Tanglewilde-Thompson Place 600 | WA5304397 | 7,900 | Ground water | 1 | Below the study levels |
| Tenino City of | WA5387400 | 3,336 | Ground water | 1 | Below the study levels |
| UNION GAP WATER | WA5390250 | 6,433 | Ground water | 4 | Below the study levels |
| UNION HILL WATER ASSOCIATION INC | WA5390260 | 8,720 | Ground water | 1 | Below the study levels |
| VANCOUVER CITY OF | WA5391200 | 373,047 | Ground water | 10 | Reached a study level |
| VERA WATER & POWER | WA5391450 | 24,692 | Ground water | 6 | Below the study levels |
| VINLAND | WA5391923 | 4,801 | Ground water | 3 | Below the study levels |
| WALLA WALLA WATER DIVISION | WA5392500 | 42,959 | Surface water | 1 | Below the study levels |
| WAPATO WATERWORKS | WA5392800 | 5,255 | Ground water | 3 | Below the study levels |
| WARDEN CITY OF | WA5392850 | 4,674 | Ground water | 4 | Below the study levels |
| WASHINGTON STATE UNIVERSITY | WA5393200 | 21,506 | Ground water | 4 | Below the study levels |
| WATER DISTRICT 19 | WA5338900 | 5,335 | Surface water | 5 | Below the study levels |
| WENATCHEE CITY OF | WA5394350 | 43,690 | Ground water | 1 | Below the study levels |
| WEST RICHLAND CITY OF | WA5394900 | 21,231 | Surface water purchased | 3 | Below the study levels |
| WEST SEQUIM BAY INC | WA5354192 | 2,759 | Ground water | 1 | Below the study levels |
| WESTPORT WATER DEPARTMENT | WA5395300 | 5,346 | Ground water | 3 | Below the study levels |
| WHATCOM COUNTY WATER DIST 13 | WA5395914 | 795 | Ground water | 2 | Below the study levels |
| WHITE SALMON CITY OF | WA5396350 | 4,077 | Surface water | 2 | Below the study levels |
| WHITWORTH WATER DISTRICT 2 | WA5396601 | 26,883 | Ground water | 9 | Below the study levels |
| WOODINVILLE WATER DISTRICT | WA5341600 | 66,699 | Surface water purchased | 1 | Below the study levels |
| WOODLAND CITY OF | WA5398200 | 10,640 | Groundwater under influence of surface water | 1 | Below the study levels |
| West Sound Utility District #1 | WA5302600 | 28,930 | Ground water | 9 | Below the study levels |
| YAK CO - TERRACE HEIGHTS | WA5306029 | 8,410 | Ground water | 5 | Below the study levels |
| YAKIMA WATER DIVISION CITY OF | WA5399150 | 112,858 | Surface water | 5 | Below the study levels |
| YELM CITY OF | WA5399350 | 17,355 | Ground water | 2 | Below the study levels |
How the count works
What is included
Each active community water system with complete monitoring is counted once, even if it is linked with several ZIP codes. Private wells are excluded, and UCMR 5 did not comprehensively monitor every small system. This page does not apply Washington's state-specific standards or determine compliance. Use the official state or territory drinking-water program for current regulatory information.