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.
| Supplier | City | State | Level vs EPA limit |
|---|---|---|---|
| Carlsbad Desalination Plant | Carlsbad | CA | 2920 µg/L 5840% of the EPA limit, in the worst sample — 50 µg/L |
| Pinedale Estates Dwid | Show Low | AZ | 1700 µg/L 3400% of the EPA limit, in the worst sample — 50 µg/L |
| Iowa Tribe of Ks & Ne | White Cloud | KS | 1700 µg/L 3400% of the EPA limit, in the worst sample — 50 µg/L |
| U.S.N., San Nicolas Island | Point Mugu | CA | 340 µg/L 680% of the EPA limit, in the worst sample — 50 µg/L |
| Kit Carson Town of | Holly | CO | 290 µg/L 580% of the EPA limit, in the worst sample — 50 µg/L |
| City of Santa Barbara Water Department | Santa Barbara | CA | 290 µg/L 580% of the EPA limit, in the worst sample — 50 µg/L |
| Resthaven Mobile Home Park | Paso Robles | CA | 230 µg/L 460% of the EPA limit, in the worst sample — 50 µg/L |
| Fullerton, City of | Fullerton | NE | 218 µg/L 436% of the EPA limit, in the worst sample — 50 µg/L |
| Heartland House | Lubbock | TX | 202 µg/L 404% of the EPA limit, in the worst sample — 50 µg/L |
| Dorrance, City of | Dorrance | KS | 200 µg/L 400% of the EPA limit, in the worst sample — 50 µg/L |
| Asgard Subdivision Wa | Silt | CO | 170 µg/L 340% of the EPA limit, in the worst sample — 50 µg/L |
| Golden State Water Company - Edna | Hawthorne | CA | 170 µg/L 340% of the EPA limit, in the worst sample — 50 µg/L |
| Alpine Springs Mobile Home Park | Palmdale | CA | 162 µg/L 324% of the EPA limit, in the worst sample — 50 µg/L |
| Oceano Comm Services Dist. | Oceano | CA | 150 µg/L 300% of the EPA limit, in the worst sample — 50 µg/L |
| Vista Hills Mutual Water Company | Lompoc | CA | 140 µg/L 280% of the EPA limit, in the worst sample — 50 µg/L |
| Valley Estates | Shallowater | TX | 135 µg/L 270% of the EPA limit, in the worst sample — 50 µg/L |
| Wayne, City of | Wayne | NE | 130 µg/L 260% of the EPA limit, in the worst sample — 50 µg/L |
| Golden State Water Co. - Robbins | Rancho Cordova | CA | 110 µg/L 220% of the EPA limit, in the worst sample — 50 µg/L |
| Sunnyside Farms Mutual Water Company | Palmdale | CA | 107 µg/L 214% of the EPA limit, in the worst sample — 50 µg/L |
| Beemer, Village of | Beemer | NE | 101 µg/L 202% of the EPA limit, in the worst sample — 50 µg/L |
| Humphrey, City of | Humphrey | NE | 101 µg/L 202% of the EPA limit, in the worst sample — 50 µg/L |
| Beverly, City of | Beverly | KS | 93 µg/L 186% of the EPA limit, in the worst sample — 50 µg/L |
| Oxnard Water Dept | Oxnard | CA | 89 µg/L 178% of the EPA limit, in the worst sample — 50 µg/L |
| Waverly, City of | Waverly | NE | 86.1 µg/L 172% of the EPA limit, in the worst sample — 50 µg/L |
| Falfurrias Utility Board | Falfurrias | TX | 84 µg/L 168% of the EPA limit, in the worst sample — 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.