Manganese is a chemical contaminant that has a reference level of 300 µg/L.
| Sanford Water District | 3960 µg/L (on 9/19/2018) | ME |
|---|---|---|
| Montara Water & Sanitary District | 3550 µg/L (on 1/20/2015) | CA |
| Pierre | 2600 µg/L (on 3/27/2018) | SD |
| Randolph Water Department | 2550 µg/L (on 12/19/2019) | MA |
| E. Bangor Municipal Authority | 2500 µg/L (on 3/14/2018) | PA |
| Regional Water Authority | 2280 µg/L (on 5/15/2019) | CT |
| Village of Kiryas Joel | 2020 µg/L (on 8/14/2019) | NY |
| City of Stanton | 1810 µg/L (on 4/7/2014) | NE |
| Valley Waters, Inc. | 1730 µg/L (on 8/6/2019) | CT |
| City of Grandview | 1590 µg/L (on 11/23/2020) | WA |
| Swansea Water District | 1490 µg/L (on 10/10/2019) | MA |
| Marysville Utilities | 1403 µg/L (on 7/23/2018) | WA |
| Southwestern Water District | 1400 µg/L (on 2/17/2015) | WV |
| Waterford Water/Sewer Association | 1351.899 µg/L (on 4/6/2015) | OH |
| Grafton Water District | 1350 µg/L (on 6/2/2020) | MA |
| Easton Water Division | 1180 µg/L (on 2/5/2019) | MA |
| City of Poulsbo | 1178 µg/L (on 3/27/2018) | WA |
| Bastrop Water | 1170 µg/L (on 7/16/2020) | LA |
| Double Springs Waterworks | 1148.986 µg/L (on 4/7/2015) | AL |
| Bayleaf Master | 1120 µg/L (on 1/29/2020) | NC |
| City of Cayce | 1120 µg/L (on 3/9/2020) | SC |
| Ventura CWWD #19 - Somis | 1100 µg/L (on 11/9/2015) | CA |
| Acton Water Supply District | 1090 µg/L (on 1/31/2019) | MA |
| City of Sumter | 1090 µg/L (on 5/29/2018) | SC |
| Endicott Municipal Waterworks | 1025.9 µg/L (on 10/8/2018) | NY |
| Bay County Water | 1019.7 µg/L (on 6/12/2018) | FL |
| City of Phoenix | 992 µg/L (on 2/7/2019) | AZ |
| The Orchard Development | 990 µg/L (on 12/9/2014) | GA |
| Oconee Co. - Watkinsville | 947 µg/L (on 9/11/2019) | GA |
| WMAUA Miner Flat | 920 µg/L (on 11/27/2018) | 09 |
| Jones County | 920 µg/L (on 8/12/2014) | GA |
| Pebble Hill Mobile Home Park | 879.65 µg/L (on 1/22/2019) | NY |
| Monticello | 872 µg/L (on 1/8/2020) | MN |
| Hecla Water Association | 868.05 µg/L (on 9/4/2019) | OH |
| IN American Water Co. - Kokomo | 860 µg/L (on 8/20/2019) | IN |
| East Lyme Water & Sewer Commission | 828 µg/L (on 9/21/2018) | CT |
| JLR | 820 µg/L (on 5/15/2013) | OR |
| Hill Air Force Base | 800 µg/L (on 6/17/2019) | UT |
| Southington Water Department | 795 µg/L (on 8/14/2018) | CT |
| City of Cohoes | 791 µg/L (on 7/23/2018) | NY |
| Arapahoe County WWWA | 764 µg/L (on 8/22/2019) | CO |
| City of Napoleon | 720 µg/L (on 4/22/2013) | ND |
| Ambler Boro Water Dept. | 720 µg/L (on 1/7/2020) | PA |
| Fernwood | 711.556 µg/L (on 4/21/2015) | PA |
| NJ American Water Co. - Atlantic County | 690 µg/L (on 6/17/2020) | NJ |
| Cedar Rapids Water Department | 687 µg/L (on 4/14/2020) | IA |
| Fort Wainwright - Main Post | 672 µg/L (on 8/22/2018) | AK |
| Keewatin | 670 µg/L (on 1/20/2015) | MN |
| Ipswich DPU Water Dept. | 657 µg/L (on 10/15/2018) | MA |
| Stringtown PWA | 640 µg/L (on 6/9/2015) | OK |