| VALPARAISO DEPARTMENT OF WATER WORKS | 36,000 | 18 | Clean |
| HEBRON WATER DEPARTMENT | 3,724 | 465 | Detected |
| L-A-C UTILITIES | 2,441 | 18 | — |
| KOUTS WATER WORKS | 2,028 | 295 | — |
| ST. ELIZABETH SETON CATHOLIC | 1,201 | 70 | — |
| OGDEN DUNES WATER | 1,110 | 48 | — |
| PORTAGE JR. MISS SOFTBALL INC. | 1,000 | 53 | — |
| CITGO - VALPARAISO | 800 | 151 | — |
| MORGAN TOWNSHIP SCHOOL | 700 | 48 | — |
| BOONE GROVE MIDDLE SCHOOL | 700 | 14 | — |
| LUKE MOBIL #202 | 671 | 92 | — |
| 49ER DRIVE IN THEATRE | 659 | 18 | — |
| HEARTLAND CHRISTIAN CENTER | 608 | 55 | — |
| BOONE GROVE HIGH SCHOOL | 600 | 72 | — |
| PORTER QUICK STOP | 502 | 164 | — |
| FOREST OAKS MHC, LLC | 500 | 104 | — |
| LIBERTY BIBLE CHURCH | 474 | 19 | — |
| DISCOVERY CHARTER SCHOOL | 454 | 4 | — |
| VALLEY BAPTIST CHURCH | 437 | 0 | — |
| JACKSON ELEMENTARY SCHOOL | 400 | 84 | — |
| LIBERTY FARMS MOBILE HOME PARK - #1 | 390 | 73 | — |
| CREEKSIDE GOLF COURSE | 306 | 86 | — |
| SUNSET HILL FARM COUNTY PARK - MANAGER | 255 | 44 | — |
| CHURCH OF JESUS CHRIST/LATTER DAY SAINTS | 250 | 62 | — |
| FAITH EVANGELICAL BIBLE CHURCH | 233 | 10 | — |
| VICTORY CHRISTIAN ACADEMY | 200 | 304 | — |
| OPEN DOOR FELLOWSHIP CHURCH | 178 | 36 | — |
| OPPORTUNITY ENTERPRISES (LAKESIDE) | 160 | 191 | — |
| FAITH FELLOWSHIP CHURCH | 156 | 39 | — |
| BLAST CAMP | 153 | 8 | — |
| MALLARDS POINTE WATER SYSTEM | 150 | 578 | — |
| BAUMS BRIDGE INN | 140 | 28 | — |
| APPLEGARTH PROPERTIES, LLC | 136 | 177 | — |
| COURTS OF NORTHWEST INDIANA - BASKETBALL | 128 | 72 | — |
| COURTS OF NORTHWEST INDIANA - TENNIS | 128 | 56 | — |
| CAMP LAWRENCE | 120 | 88 | — |
| PORTAGE PARKS DEPT - IMAGINATION GLEN | 120 | 65 | — |
| LEROYS HOT STUFF | 110 | 239 | — |
| FORCHETTI FAMILY YMCA | 105 | 162 | — |
| FAMILY EXPRESS - DISTRIBUTION CENTER | 102 | 171 | — |
| PRINCE OF PEACE LUTHERAN CHURCH | 100 | 124 | — |
| SALEM UNITED METHODIST FELLOWSHIP | 100 | 21 | — |
| FAITH MEMORIAL LUTHERAN CHURCH | 98 | 103 | — |
| CROSS OF CHRIST LUTHERAN CHURCH | 96 | 28 | — |
| KINGDOM HALL JEHOVAHS WITNESSES - HEBRON | 88 | 11 | — |
| IN DUNES NATL LAKESHORE-BLDGS 101-119 | 80 | 114 | — |
| KINGDOM HALL OF JEHOVAHS WITNESSES | 78 | 13 | — |
| GABIS ARBORETUM AT PURDUE NW- DEPOT | 75 | 29 | — |
| GABIS ARBORETUM AT PURDUE NW - PAVILION | 75 | 11 | — |
| SHELLBOURNE CONFERENCE CENTER | 72 | 55 | — |