| SANTA ROSA, CITY OF | 175,396 | 4 | Detected |
| PETALUMA, CITY OF | 60,781 | 4 | Clean |
| ROHNERT PARK, CITY OF | 43,821 | 561 | Detected |
| WINDSOR, TOWN OF | 25,561 | 6 | Clean |
| VALLEY OF THE MOON WATER DISTRICT | 23,107 | 9 | Detected |
| SONOMA, CITY OF | 11,725 | 17 | Detected |
| SONOMA STATE UNIVERSITY | 10,986 | 22 | Detected |
| HEALDSBURG, CITY OF | 10,985 | 11 | Detected |
| CLOVERDALE, CITY OF | 10,398 | 24 | Clean |
| CALIFORNIA-AMERICAN LARKFIELD (PUC) | 7,913 | 6 | Detected |
| SEBASTOPOL, CITY OF | 7,522 | 19 | Detected |
| COTATI, CITY OF | 7,303 | 3 | Detected |
| SWEETWATER SPRINGS CWD - GUERNEVILLE | 6,000 | 7 | Clean |
| RUSSIAN RIVER COUNTY WATER DISTRICT | 4,150 | 13 | Clean |
| FORESTVILLE WATER DISTRICT | 3,788 | 2 | — |
| CSP-SALT POINT STATE PARK | 3,513 | 1 | — |
| CSP-FORT ROSS STATE PARK | 3,501 | 17 | — |
| SWEETWATER SPRINGS CWD - MONTE RIO | 3,000 | 0 | — |
| PENNGROVE WATER COMPANY (PUC) | 1,742 | 19 | — |
| SONOMA COUNTY CSA 41-FITCH MOUNTAIN | 1,265 | 5 | — |
| CAMP MEEKER WATER SYSTEM | 1,171 | 0 | — |
| SEA RANCH WATER COMPANY,THE (PUC) | 1,160 | 11 | Detected |
| BODEGA BAY PUBLIC UTILITY DISTRICT | 1,069 | 7 | — |
| CALIFORNIA-AMERICAN GEYSERVILLE (PUC) | 1,046 | 1 | Clean |
| KENWOOD VILLAGE WATER COMPANY (PUC) | 1,029 | 8 | — |
| SUTTER SANTA ROSA REGIONAL HOSPITAL | 1,000 | 0 | — |
| CANON MANOR WATER SYSTEM | 805 | 6 | — |
| ODD FELLOWS RECREATION CLUB | 757 | 8 | — |
| URJ CAMP NEWMAN | 705 | 7 | — |
| MOON VALLEY WATER SYSTEM | 691 | 4 | — |
| JEHOVAH S WITNESSES HALL | 650 | 8 | — |
| DIAMOND A MUTUAL WATER COMPANY | 640 | 18 | — |
| CSP-ARMSTRONG REDWOODS STATE RESERVE | 611 | 0 | — |
| KORBEL BROTHERS WINERY | 546 | 8 | — |
| OCCIDENTAL COMMUNITY SERVICES DISTRICT | 533 | 25 | — |
| CAZADERO WATER COMPANY, INC. (PUC) | 525 | 57 | — |
| CSP-WRIGHTS BEACH STATE PARK | 502 | 4 | — |
| WRIGHT ELEMENTARY SCHOOL | 500 | 7 | — |
| OAK GROVE SCHOOL | 500 | 10 | — |
| CLINE CELLARS | 500 | 10 | — |
| ARMSTRONG VALLEY-CAL WATER SERVICE (PUC) | 473 | 1 | — |
| U.S. COAST GUARD TRAINING CENTER | 469 | 7 | — |
| RINCON VALLEY MOBILE ESTATES | 460 | 14 | — |
| WILLOWSIDE SCHOOL | 460 | 6 | — |
| WILLOWSIDE MUTUAL WATER COMPANY | 448 | 16 | — |
| CASINI RANCH CAMPGROUND | 442 | 9 | — |
| BENNETT RIDGE MUTUAL WATER COMPANY | 439 | 9 | — |
| SERENO DEL MAR WATER COMPANY (PUC) | 435 | 19 | — |
| SONOMA COUNTY CSA 41-SALMON CREEK | 427 | 15 | — |
| SANTA ROSA MOBILE ESTATES | 420 | 9 | — |