| MICHIGAN CITY DEPARTMENT OF WATER WORKS | 33,996 | 68 | Clean |
| LAPORTE WATER WORKS | 22,197 | 10 | Detected |
| WESTVILLE CORRECTIONAL FACILITY | 2,850 | 83 | — |
| LONG BEACH WATER DEPARTMENT | 2,050 | 344 | — |
| SOUTH COAST CONSERVANCY DISTRICT | 2,013 | 9 | — |
| NEW PRAIRIE SCHOOLS | 1,800 | 117 | — |
| KINGSFORD HEIGHTS WATER | 1,800 | 27 | — |
| WESTVILLE WATER DEPARTMENT | 1,800 | 159 | — |
| SPEEDWAY SUPERAMERICA LLC - US 35 #6661 | 1,618 | 23 | — |
| FAMILY EXPRESS #19 - SPRINGVILLE | 1,406 | 80 | — |
| MICHIGAN CITY REST AREA - INDOT | 1,200 | 35 | — |
| SPEEDWAY #6748 | 1,110 | 52 | — |
| NEW DURHAM ESTATES | 1,099 | 24 | — |
| WANATAH WATER UTILITY | 1,050 | 15 | — |
| SOUTH CENTRAL ELEMENTARY/JR./SR. HIGH | 1,047 | 51 | — |
| GALLOPS SERVICE STATION - LAPORTE | 805 | 167 | — |
| PATRIOT PARK | 707 | 59 | — |
| LAPORTE COUNTY REGIONAL SWD | 675 | 8 | — |
| ROLLING PRAIRIE ELEMENTARY | 570 | 115 | — |
| FAMILY EXPRESS - STORE #59 | 555 | 47 | — |
| LACROSSE WATER DEPARTMENT | 540 | 107 | — |
| TC FOOD MART | 504 | 44 | — |
| CROSSROADS TOBACCO/VAQUEROS | 504 | 27 | — |
| KINGSFORD EXPO 66 | 503 | 183 | — |
| COOLSPRING ELEMENTARY SCHOOL | 460 | 40 | — |
| SPRINGFIELD ELEMENTARY SCHOOL | 445 | 118 | — |
| ROAD TO LIFE CHURCH | 420 | 94 | — |
| INDIAN TRAIL ELEMENTARY SCHOOL | 411 | 38 | — |
| CRAFT STATION | 405 | 260 | — |
| KINGSBURY ELEMENTARY SCHOOL | 400 | 40 | — |
| PRAIRIE VIEW ELEMENTARY SCHOOL | 370 | 870 | — |
| WESTVILLE ESTATES | 315 | 789 | — |
| J. B. WATER WORKS, INC. | 307 | 28 | — |
| PLAZA 30 | 305 | 134 | — |
| DUNELAND BEACH ASSOCIATION | 300 | 32 | — |
| RENAISSANCE ACADEMY | 285 | 1,552 | — |
| WESTVILLE TRUCK STOP | 273 | 211 | — |
| ST. MARYS CATHOLIC CHURCH-RECTORY/CHURCH | 260 | 69 | — |
| DOLLAR GENERAL - ROLLING PRAIRIE | 258 | 3 | — |
| FAMILY EXPRESS #13 - JOHNSON ROAD | 253 | 62 | — |
| ST. JOHN KANTY PARISH HALL | 250 | 11 | — |
| LALUMIERE SCHOOL | 245 | 87 | — |
| KINGSBURY UTILITY CORPORATION | 240 | 249 | — |
| HESTON SUPPER CLUB | 210 | 51 | — |
| N.P WESTVILLE INDUSTRIAL, LLC | 204 | 157 | — |
| LAPORTE ASSEMBLY OF GOD CHURCH | 203 | 15 | — |
| WANATAH CHRISTIAN CHURCH | 171 | 33 | — |
| GARWOOD FARM MARKET | 170 | 21 | — |
| FAMILY EXPRESS #51 - KINGSBURY | 153 | 55 | — |
| ST. ANTHONY CATHOLIC CHURCH | 151 | 12 | — |