Free testing, with limits
New Mexico offers free screening at water fairs and some field offices, but it doesn't replace a certified lab test. Check which tests it includes before you count on it for arsenic.
New Mexico's private well pageArsenic in New Mexico well water, by county
Arsenic is widespread, over the limit in 15% or more of tested wells, in 5 of the 15 New Mexico counties with 10 or more tested wells. A county's share tells you how likely a problem is nearby. Only a test of your own well tells you what's in it.
How New Mexico compares with the rest of the country
Across New Mexico, about 1 in 7 tested wells had arsenic over the EPA limit of 10 µg/L (100 of 723). Across all tested wells in the US it's about 1 in 9. New Mexico is about average, so the county you live in tells you more than the state does.
Why it matters: Drinking it for years raises the risk of skin, bladder and lung cancer.
Arsenic dissolves out of certain rocks and old sediments, so it can be high even where nobody has polluted anything.
Arsenic in tested wells, county by county
Share of each county's tested wells with at least one result over the EPA limit of 10 µg/L. Counties need 10 or more tested wells to be listed. Widespread means 15% or more, worth checking 5 to 15%, rare under 5%.
| County | Wells tested | Wells over the limit | Level |
|---|---|---|---|
| Sandoval County | 28 | Widespread | |
| Rio Arriba County | 36 | Widespread | |
| Cibola County | 23 | Widespread | |
| Bernalillo County | 170 | Widespread | |
| Doña Ana County | 151 | Widespread | |
| Otero County | 41 | Worth checking | |
| San Juan County | 46 | Worth checking | |
| Catron County | 19 | Worth checking | |
| Valencia County | 10 | Worth checking | |
| Roosevelt County | 38 | Worth checking | |
| Santa Fe County | 21 | Rare | |
| Curry County | 51 | Rare | |
| Lincoln County | 23 | Rare | |
| McKinley County | 13 | Rare | |
| Sierra County | 11 | Rare |
8 more New Mexico counties have 1 to 9 tested wells for arsenic, too few to rate.
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Where to get your well tested for arsenic in New Mexico
A lab New Mexico certifies
Ask for arsenic by name. Results from a certified lab count for a home sale or a loan.
Labs certified by New MexicoA mail-in kit
Fill the bottles at your kitchen tap and mail them back. We mark the kits that include arsenic.
Compare kitsKeep reading about wells in New Mexico
- Well water testing in New Mexico: how to get tested and what turns up statewide
- Arsenic in well water: where it comes from, what it does and how to remove it
- Nitrate in New Mexico wells, by county
- Uranium in New Mexico wells, by county
- Manganese in New Mexico wells, by county
- Lead in New Mexico wells, by county
Questions people ask about arsenic in New Mexico
Is there arsenic in New Mexico well water?
Arsenic is widespread, over the limit in 15% or more of tested wells, in 5 of the 15 New Mexico counties with 10 or more tested wells. Across New Mexico, about 1 in 7 tested wells had arsenic over the EPA limit of 10 µg/L (100 of 723). Across all tested wells in the US it's about 1 in 9. New Mexico is about average, so the county you live in tells you more than the state does.
Where can I get my well tested for arsenic in New Mexico?
New Mexico offers free screening at water fairs and some field offices, but it doesn't replace a certified lab test. If that doesn't cover you, use a lab certified by New Mexico for drinking water, or a mail-in kit that includes arsenic from a certified lab.
See New Mexico's list of certified labs, or compare mail-in kits.
Where these numbers come from
- Lab tests: Water Quality Portal (USGS and EPA), well samples since 2000. A well counts as over if any of its tests was over the EPA limit of 10 µg/L. Wells tested for studies and monitoring, not a random sample of homes.
- Likely overstated: our own check of who tested the wells, when and where. How we check.
- State programs and links: Environment Department.