| ARTONDALE | | 5,828 | 0.1536 ug/L |
| MOSES LAKE CITY OF | | 32,428 | 0.0522 ug/L |
| VANCOUVER CITY OF | | 373,047 | 0.0186 ug/L |
| RICHLAND CITY OF | | 106,499 | 0.0170 ug/L |
| PARKLAND LIGHT & WATER COMPANY | | 33,775 | 0.0138 ug/L |
| CAMAS MUNICIPAL WATER SEWER SYSTEM | | 31,794 | 0.0120 ug/L |
| TRENTWOOD IRRIGATION DISTRICT 3 | | 4,228 | 0.0120 ug/L |
| QUISTORFF | | 1,113 | 0.0120 ug/L |
| KENNEWICK CITY OF | | 118,164 | 0.0115 ug/L |
| SAMMAMISH PLATEAU WATER & SEWER | | 79,362 | 0.0111 ug/L |
| JBLM Lewis | | 35,414 | 0.0111 ug/L |
| COUPEVILLE TOWN OF | | 4,142 | 0.0098 ug/L |
| SOUTHWOOD | | 64,155 | 0.0089 ug/L |
| BENTON CITY WATER | | 5,626 | 0.0087 ug/L |
| COVINGTON WATER DISTRICT | | 56,172 | 0.0086 ug/L |
| FIRGROVE MUTUAL INC | | 36,168 | 0.0086 ug/L |
| CLARK PUBLIC UTILITIES | | 153,526 | 0.0084 ug/L |
| SPANAWAY WATER COMPANY | | 34,506 | 0.0083 ug/L |
| WASHOUGAL CITY OF | | 21,441 | 0.0079 ug/L |
| FAIRCHILD AIR FORCE BASE | | 9,544 | 0.0079 ug/L |
| DEER PARK CITY OF | | 5,435 | 0.0075 ug/L |
| SPOKANE CITY OF | | 346,138 | 0.0061 ug/L |
| LAKEWOOD WATER DISTRICT | | 82,425 | 0.0059 ug/L |
| OLYMPIA CITY OF | | 126,966 | 0.0058 ug/L |
| CENTRALIA PUBLIC WORKS - WATER | | 28,164 | 0.0058 ug/L |
| West Sound Utility District #1 | | 28,930 | 0.0057 ug/L |
| EAST SPOKANE WATER DIST 1 | | 4,285 | 0.0055 ug/L |
| JBLM McChord Field | | 7,290 | 0.0053 ug/L |
| REDMOND WATER SYSTEM CITY OF | | 163,335 | 0.0050 ug/L |
| WHITWORTH WATER DISTRICT 2 | | 26,883 | 0.0046 ug/L |
| MEDICAL LAKE CITY OF | | 4,982 | 0.0044 ug/L |
| MODEL IRRIGATION DIST #18 | | 7,903 | 0.0042 ug/L |
| LAKEHAVEN WATER AND SEWER DISTRICT | | 148,809 | 0.0041 ug/L |
| FRUITLAND MUTUAL WATER COMPANY | | 15,313 | 0.0040 ug/L |
| SEATTLE PUBLIC UTILITIES | | 1,161,961 | Not detected |
| TACOMA WATER DIVISION CITY OF | | 446,170 | Not detected |
| BELLEVUE CITY OF | | 321,349 | Not detected |
| ALDERWOOD WATER DISTRICT | | 245,715 | Not detected |
| EVERETT PUBLIC WORKS DEPT. CITY OF | | 215,774 | Not detected |
| KENT WATER DEPARTMENT | | 166,421 | Not detected |
| BELLINGHAM-WATER DIVISION CITY OF | | 141,127 | Not detected |
| PASCO WATER DEPARTMENT | | 115,102 | Not detected |
| YAKIMA WATER DIVISION CITY OF | | 112,858 | Not detected |
| SKAGIT COUNTY PUD 1 JUDY RES | | 111,415 | Not detected |
| RENTON CITY OF | | 108,091 | Not detected |
| Auburn City of | | 107,655 | Not detected |
| LACEY WATER DEPARTMENT | | 105,178 | Not detected |
| HIGHLINE WATER DISTRICT | | 100,170 | Not detected |
| NORTHSHORE UTILITY DISTRICT | | 99,789 | Not detected |
| PUYALLUP CITY OF | | 94,520 | Not detected |
| MARYSVILLE UTILITIES | | 88,582 | Not detected |
| SOOS CREEK WATER & SEWER DISTRICT | | 74,172 | Not detected |
| BREMERTON CITY OF | | 72,951 | Not detected |
| KIRKLAND CITY OF | | 69,243 | Not detected |
| LYNNWOOD CITY OF | | 68,204 | Not detected |
| SNO PUD 1 - LAKE STEVENS | | 67,710 | Not detected |
| WOODINVILLE WATER DISTRICT | | 66,699 | Not detected |
| SILVER LAKE WATER & SEWER DISTRICT | | 65,033 | Not detected |
| LONGVIEW WATER DEPARTMENT | | 57,617 | Not detected |
| TUMWATER CITY OF | | 51,802 | Not detected |
| KING COUNTY WATER DISTRICT #20 | | 48,469 | Not detected |
| WENATCHEE CITY OF | | 43,690 | Not detected |
| ISSAQUAH WATER SYSTEM | | 43,584 | Not detected |
| BONNEY LAKE WATER DEPARTMENT CITY | | 43,371 | Not detected |
| WALLA WALLA WATER DIVISION | | 42,959 | Not detected |
| NOB HILL WATER ASSOCIATION | | 38,050 | Not detected |
| TUKWILA WATER DEPARTMENT | | 36,298 | Not detected |
| SILVERDALE WATER DIST 16 | | 35,163 | Not detected |
| EDMONDS CITY OF | | 34,065 | Not detected |
| BOTHELL WATER CITY OF | | 33,643 | Not detected |
| North City Water District | | 32,847 | Not detected |
| Mukilteo Water & Wastewater Distr | | 31,437 | Not detected |
| PULLMAN WATER DEPARTMENT CITY OF | | 31,315 | Not detected |
| MERCER ISLAND CITY OF | | 31,057 | Not detected |
| ARLINGTON CITY OF | | 29,508 | Not detected |
| FIFE DEPT OF PUBLIC WORKS | | 29,091 | Not detected |
| CEDAR RIVER WATER & SEWER DISTRICT | | 28,671 | Not detected |
| PORT ANGELES CITY OF | | 28,067 | Not detected |
| EAST WENATCHEE WATER DISTRICT | | 26,519 | Not detected |
| MOUNTLAKE TERRACE CITY OF | | 26,402 | Not detected |
| ANACORTES CITY OF | | 25,109 | Not detected |
| CROSS VALLEY WATER DISTRICT | | 24,695 | Not detected |
| VERA WATER & POWER | | 24,692 | Not detected |
| NORTH PERRY AVE WATER DISTRICT | | 24,402 | Not detected |
| Lake Meridian Water District | | 24,231 | Not detected |
| OAK HARBOR CITY OF | | 23,675 | Not detected |
| KING COUNTY WATER DISTRICT #49 | | 23,492 | Not detected |
| MONROE WATER SYSTEM | | 23,467 | Not detected |
| ENUMCLAW WATER DEPARTMENT | | 23,276 | Not detected |
| ABERDEEN CITY OF | | 22,867 | Not detected |
| PUD #1 OF ASOTIN COUNTY | | 21,930 | Not detected |
| KING COUNTY WATER DISTRICT #125 | | 21,904 | Not detected |
| WASHINGTON STATE UNIVERSITY | | 21,506 | Not detected |
| WEST RICHLAND CITY OF | | 21,231 | Not detected |
| RIDGEFIELD PUBLIC WORKS | | 21,225 | Not detected |
| CONSOLIDATED IRRIG DIST 19 SYSTEM 2 | | 21,220 | Not detected |
| ELLENSBURG WATER DEPT | | 20,900 | Not detected |
| SNOQUALMIE WATER | | 20,222 | Not detected |
| KING COUNTY WATER DISTRICT NO 90 | | 20,100 | Not detected |
| LYNDEN WATER DEPARTMENT | | 20,062 | Not detected |