What Selenium is, and why it's regulated
What the EPA limit means
50 µg/L
Maximum Contaminant Level — the enforceable ceiling a supplier must stay under.
50 µg/L
Health goal (MCLG) — the level with no known health effect. It is a goal, not a legal limit, and is often zero for carcinogens.
SYR4
Where these measurements come from. Hover the tag for the EPA programme and years.
Where Selenium was found
The water suppliers reporting the highest levels, worst first. For lead and copper that is the 90th-percentile result the action level is written against; for Six-Year Review data, the 95th percentile of each system's samples.
| Supplier | City | State | Level vs EPA limit |
|---|---|---|---|
| Carlsbad Desalination Plant | Carlsbad | CA | 1900.87 µg/L 3802% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Iowa Tribe of Ks & Ne | White Cloud | KS | 1615.12 µg/L 3230% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Pinedale Estates Dwid | Show Low | AZ | 1434 µg/L 2868% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| U.S.N., San Nicolas Island | Point Mugu | CA | 328.3 µg/L 657% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| City of Santa Barbara Water Department | Santa Barbara | CA | 254 µg/L 508% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Resthaven Mobile Home Park | Paso Robles | CA | 210 µg/L 420% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Heartland House | Lubbock | TX | 183.95 µg/L 368% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Fullerton, City of | Fullerton | NE | 179.4 µg/L 359% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Alpine Springs Mobile Home Park | Palmdale | CA | 162 µg/L 324% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Asgard Subdivision Wa | Silt | CO | 152 µg/L 304% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Vista Hills Mutual Water Company | Lompoc | CA | 138 µg/L 276% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Oceano Comm Services Dist. | Oceano | CA | 130 µg/L 260% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Valley Estates | Shallowater | TX | 129.4 µg/L 259% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Golden State Water Co. - Robbins | — | CA | 110 µg/L 220% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Sunnyside Farms Mutual Water Company | Palmdale | CA | 107 µg/L 214% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Golden State Water Company - Edna | — | CA | 98 µg/L 196% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Dorrance, City of | Dorrance | KS | 92.45 µg/L 185% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Beverly, City of | Beverly | KS | 88.45 µg/L 177% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Humphrey, City of | Humphrey | NE | 78.68 µg/L 157% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Beemer, Village of | Beemer | NE | 78.09 µg/L 156% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Green River Mutual Water Co. | Paso Robles | CA | 78 µg/L 156% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Burr Oak, City of | Burr Oak | KS | 74.4 µg/L 149% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Sky Ranch Estates | Sandy Valley | NV | 74.28 µg/L 149% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Falfurrias Utility Board | Falfurrias | TX | 72.22 µg/L 144% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
| Bookwalter Woods Mhp | Gardner | IL | 70.96 µg/L 142% of the EPA limit, at the 95th percentile of samples — 50 µg/L |
Frequently asked questions about Selenium
What is Selenium in drinking water?
Selenium is a natural mineral that is essential in trace amounts but causes hair loss and circulation problems in excess.
What is the EPA limit for Selenium?
The EPA's Maximum Contaminant Level for Selenium is 50 µg/L, and its health goal (MCLG) is 50 µg/L. A result above the limit means the supplier must act; the goal is the level at which no health effects are expected.
How common is Selenium in US tap water?
Of the 33,730 water suppliers with results on file, 7,995 detected Selenium — 23.7% of those tested.