| WESTERLY WATER DEPARTMENT | 35,298 | 344 | Detected |
| NORTH KINGSTOWN TOWN OF | 27,732 | 321 | Detected |
| VEOLIA WATER WAKEFIELD RHODE ISLAND INC | 22,347 | 86 | Clean |
| UNIVERSITY OF RHODE ISLAND | 19,354 | 198 | Detected |
| QUONSET BUSINESS PARK | 13,000 | 259 | Detected |
| BLOCK ISLAND WATER COMPANY | 9,999 | 378 | Clean |
| NARRAGANSETT WATER SYSTEM-POINT JUDITH | 8,210 | 115 | Clean |
| SOUTH KINGSTOWN-SOUTH SHORE | 6,170 | 108 | Detected |
| NARRAGANSETT WATER DEPT-NORTH END | 4,432 | 130 | Detected |
| KINGSTON WATER DISTRICT | 3,968 | 317 | Detected |
| BURLINGAME RESERVATION-MAIN CAMP-LEGIONT | 3,024 | 88 | — |
| RICHMOND, TOWN OF | 2,671 | 145 | — |
| RHODE ISLAND WELCOME CENTER | 2,000 | 11 | — |
| CHARIHO REGIONAL MIDDLE SCHOOL | 1,500 | 10 | — |
| CHARIHO REGIONAL HIGH SCHOOL | 1,300 | 27 | — |
| YAWGOOG SCOUT RESERVATION | 1,200 | 54 | — |
| HARBORSIDE INN, INC. | 1,000 | 24 | — |
| TDS REALTY HOLDINGS - AN0 | 1,000 | 36 | — |
| WAWALOAM RV LLC DBA WAWALOAM CAMPGROUND | 750 | 91 | — |
| SOUTH KINGSTOWN-MIDDLEBRIDGE | 694 | 38 | — |
| METCALF ELEMENTARY SCHOOL | 687 | 27 | — |
| WHISPERING PINES CAMPGROUND | 600 | 24 | — |
| ASHAWAY PINES RV RESORT LLC | 520 | 15 | — |
| DOWNEY WEAVER POST #34 AMERICAN LEGION | 500 | 5 | — |
| ALLIES DONUTS, INC. | 500 | 59 | — |
| CORNER DELI, THE | 500 | 34 | — |
| CENTRAL BEACH FIRE DISTRICT | 470 | 146 | — |
| SPRING HOUSE HOTEL -ISLAND ENTERTAINMENT | 450 | 25 | — |
| FRONTIER CAMPER PARK INC | 438 | 60 | — |
| BLOCK ISLAND AIRPORT OPERATIONS | 400 | 47 | — |
| PINECREST GOLF COURSE, INC. | 400 | 5 | — |
| LONG COVE MARINA & CAMPGROUND | 375 | 19 | — |
| CHARLESTOWN ELEMENTARY SCHOOL | 350 | 18 | — |
| MEADOW BROOK INN, LTD. | 350 | 35 | — |
| BURLINGAME PARK-PROSSER BEACH-PICNIC AN0 | 305 | 21 | — |
| YMCA CAMP FULLER | 305 | 224 | — |
| SHADY HARBOR FIRE DISTRICT | 300 | 12 | — |
| QUONOCHONTAUG EAST BEACH WATER ASSOCIATI | 300 | 360 | — |
| ASHAWAY ELEMENTARY SCHOOL | 300 | 17 | — |
| CHARLESTOWN RATHSKELLER TAVERN INC. | 300 | 16 | — |
| HOLLY TREE CAMPER PARK, INC. | 300 | 20 | — |
| CHAMPLINS MARINA & RESORTS, INC. | 300 | 74 | — |
| EXETER CHAPEL | 300 | 17 | — |
| SHADOW WOODS AT DEER BROOK | 300 | 120 | — |
| CHARIHO SOUTHERN BAPTIST CHURCH | 300 | 35 | — |
| EXETER JOB CORPS CENTER | 300 | 53 | — |
| CASTLE ROCK CONDOMINIUMS | 292 | 48 | — |
| WAWALOAM SCHOOL | 290 | 10 | — |
| OAK HARBOR VILLAGE, LLC. | 290 | 31 | — |
| KINGSTON HILL ACADEMY | 285 | 5 | — |