| UKIAH, CITY OF | 16,607 | 4 | Detected |
| FORT BRAGG, CITY OF | 6,919 | 12 | Clean |
| WILLITS, CITY OF | 6,175 | 28 | Clean |
| MILLVIEW COUNTY WATER DISTRICT | 5,500 | 6 | Clean |
| REDWOOD VALLEY COUNTY WATER DISTRICT | 5,200 | 12 | Clean |
| WILLOW COUNTY WATER DISTRICT | 3,797 | 7 | Clean |
| BROOKTRAILS TOWNSHIP CSD | 3,632 | 7 | Clean |
| NORTH GUALALA WATER COMPANY | 2,593 | 11 | — |
| ROGINA WATER COMPANY INC. | 2,554 | 7 | — |
| CSP-VAN DAMME STATE PARK | 2,004 | 7 | — |
| U.S. ARMY CORPS-LAKE MENDO (BUSHAY SITE) | 2,000 | 2 | — |
| U.S. ARMY CORPS-LAKE MENDO (KYEN CMPGRD) | 1,500 | 6 | — |
| CSP-MACKERRICHER STATE PARK | 1,416 | 10 | — |
| LAYTONVILLE COUNTY WATER DISTRICT | 1,152 | 34 | — |
| HOPLAND PUBLIC UTILITY DISTRICT | 1,076 | 27 | — |
| MENDOCINO SCHOOL DISTRICT- MENDOCINO | 579 | 9 | — |
| DOLPHIN ISLE MARINA | 560 | 12 | — |
| CALPELLA COUNTY WATER DISTRICT | 548 | 11 | — |
| TESORO 68137 | 508 | 2 | — |
| CSP-STANDISH HICKEY STATE REC AREA | 503 | 9 | — |
| MENDOCINO COUNTY FAIRGROUNDS | 500 | 2 | — |
| CSP-MENDOCINO HEADLANDS-SEA ARCH | 500 | 0 | — |
| POINT ARENA WATER WORKS | 459 | 5 | — |
| CSP-PT. CABRILLO LIGHT STATION SHP | 430 | 2 | — |
| ALBION RIVER CAMPGROUND | 425 | 17 | — |
| WENTE SCOUT RESERVATION | 422 | 15 | — |
| CSP-MANCHESTER STATE PARK | 420 | 7 | — |
| MOSS COVE REST STOP (CALTRANS) | 400 | 0 | — |
| CSP-MENDOCINO WOODLANDS | 400 | 8 | — |
| CITY OF 10,000 BUDDHAS | 400 | 29 | — |
| ELK COUNTY WATER DISTRICT | 380 | 10 | — |
| CSP-WESTPORT STATE BEACH | 370 | 6 | — |
| WESTPORT COUNTY WATER DISTRICT | 369 | 55 | — |
| HIDDEN PINES CAMPGROUND | 362 | 8 | — |
| ANDERSON VALLEY ELEMENTARY SCHOOL | 350 | 16 | — |
| CAMP MENDOCINO | 321 | 18 | — |
| PINE MOUNTAIN MUTUAL WATER CO. | 310 | 19 | — |
| POTTER VALLEY SCHOOL DISTRICT | 309 | 17 | — |
| IRVINE LODGE REST STOP (CALTRANS) | 300 | 2 | — |
| EMPIRE REST STOP (CALTRANS) | 300 | 0 | — |
| U.S. ARMY CORPS-LAKE MENDO (POMO SITE) | 300 | 4 | — |
| ANDERSON VALLEY HIGH SCHOOL | 300 | 14 | — |
| ROUND VALLEY ELEMENTARY SCHOOL | 289 | 8 | — |
| CAMP NAVARRO | 284 | 6 | — |
| WOODSIDE RV PARK | 280 | 20 | — |
| CSP-MENDOCINO HEADLANDS - FORD HOUSE | 275 | 2 | — |
| MANCHESTER BEACH KOA | 273 | 4 | — |
| RIDGEWOOD WATER SYSTEM | 265 | 25 | — |
| GREEN ACRES TRAILER PARK | 256 | 4 | — |
| IRISH BEACH WATER DISTRICT | 254 | 13 | — |