| SLIDELL WATER SUPPLY | 35,547 | 98 | Detected |
| ST TAM PARISH- BEDICO -FAUBOURG-COQUILLE | 18,372 | 9 | Detected |
| ST TAM PARISH - BRIARWOOD TERRACE | 17,536 | 48 | Detected |
| COVINGTON WATER SUPPLY | 16,185 | 76 | Detected |
| MANDEVILLE WATER SUPPLY | 13,000 | 23 | Detected |
| UTILITIES INC - NORTH PARK WATER SUPPLY | 11,298 | 27 | Detected |
| BAYOU LIBERTY WATER ASSOCIATION | 10,791 | 65 | Detected |
| MAGNOLIA-EDEN ISLES | 10,155 | 28 | Detected |
| MAGNOLIA-GREENLEAVES | 8,031 | 47 | Detected |
| ST TAM PARISH - CROSS GATES SD | 7,791 | 49 | Detected |
| MAGNOLIA-RESOLVE WHISPERWOOD | 6,867 | 13 | Detected |
| UTILITIES INC - KINGSPOINT SUBDIVISION | 6,351 | 13 | Detected |
| LEE ROAD WATER CORPORATION | 6,048 | 25 | Detected |
| ST. TAMMANY WATER DISTRICT #2 | 5,200 | 36 | Clean |
| MAGNOLIA-THE MEADOWS | 4,701 | 21 | Detected |
| BEAU CHENE WATER SYSTEM | 4,650 | 12 | Detected |
| MAGNOLIA-LAKESHORE ESTATES | 4,146 | 36 | — |
| ABITA SPRINGS WATER SYSTEM | 3,693 | 47 | Detected |
| TOWN OF PEARL RIVER | 3,333 | 22 | Clean |
| ST TAMMANY WATER DISTRICT 3 | 2,920 | 106 | — |
| MAGNOLIA-GUSTE ISLAND | 2,847 | 9 | — |
| UTILITIES INC - LAKE VILLAGE SD | 2,724 | 4 | — |
| ST TAM PARISH PINELAND PARK SUBD | 2,500 | 15 | — |
| UTILITIES INC - GREEN BRIER WATER SUPPLY | 2,250 | 36 | — |
| UTILITIES INC - HUNTWYCK VILLAGE | 2,088 | 13 | — |
| PELICAN PARK | 2,000 | 28 | — |
| FOLSOM WATER SUPPLY | 1,992 | 32 | Clean |
| ST TAM PARISH -NORTHRIDGE ESTATES | 1,653 | 3 | — |
| UTILITIES INC - MAGNOLIA FOREST SUBD | 1,635 | 11 | — |
| UTILITIES INC - WOODRIDGE SUBDIVISION | 1,590 | 6 | — |
| UTILITIES INC - QUAIL RIDGE SUBDIVISION | 1,563 | 13 | — |
| MAGNOLIA-MONTEREY SUBDIVISION | 1,356 | 39 | — |
| TCHEFUNCTA CLUB ESTATES | 1,245 | 38 | — |
| MAGNOLIA-PENN MILL LAKES | 1,152 | 17 | — |
| ST TAM PARISH - MEDCATH (LA HEART) | 1,001 | 6 | — |
| FONTAINEBLEAU STATE PARK | 1,000 | 65 | — |
| KNIGHTS OF COLUMBUS BINGO | 1,000 | 4 | — |
| WINN DIXIE #1500 | 1,000 | 11 | — |
| LACOMBE STORES | 999 | 3 | — |
| ST TAM PARISH - RIVER OAKS | 930 | 1 | — |
| ARBY'S | 900 | 20 | — |
| VILLAGES OF BOCAGE- MADISONVILLE | 894 | 18 | — |
| MAYFIELD ELEMENTARY SCHOOL | 890 | 7 | — |
| MADISONVILLE WATER SUPPLY | 871 | 8 | — |
| LAKE RAMSEY | 840 | 125 | — |
| MAGNOLIA-MONEY HILLS ESTATES | 825 | 18 | — |
| MAGNOLIA-RIVER PARK | 822 | 0 | — |
| SUNNY TIMES 4 LLC | 750 | 7 | — |
| LAKESHORE HIGH SCHOOL | 750 | 4 | — |
| SUN WATER SUPPLY | 726 | 129 | — |