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 nitrate.
New Mexico's private well pageNitrate in New Mexico well water, by county
Nitrate is widespread, over the limit in 15% or more of tested wells, in 2 of the 14 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 10 tested wells had nitrate over the EPA limit of 10 mg/L (76 of 760). Across all tested wells in the US it's about 1 in 12. New Mexico is about average, so the county you live in tells you more than the state does.
Why it matters: It's dangerous for babies under 6 months, because it keeps their blood from carrying enough oxygen.
Nitrate soaks down into groundwater from fertilizer, manure and septic systems.
Nitrate in tested wells, county by county
Share of each county's tested wells with at least one result over the EPA limit of 10 mg/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 |
|---|---|---|---|
| Valencia County | 17 | Widespread | |
| San Juan County | 52 | Widespread | |
| Otero County | 41 | Worth checking | |
| Doña Ana County | 198 | Worth checking | |
| Bernalillo County | 174 | Worth checking | |
| Roosevelt County | 40 | Worth checking | |
| Sierra County | 12 | Worth checking | |
| Cibola County | 20 | Worth checking | |
| Lincoln County | 22 | Rare | |
| Curry County | 53 | Rare | |
| Rio Arriba County | 36 | Rare | |
| Sandoval County | 33 | Rare | |
| Santa Fe County | 18 | Rare | |
| McKinley County | 13 | Rare |
* Likely overstated. These shares come from a narrow set of wells, so they probably run high for the county as a whole:
- Sierra County: All of these tests come from the US Geological Survey in one small part of the county, so it may not match the rest of the county.
- Cibola County: All of these tests come from the US Geological Survey in one small part of the county, so it may not match the rest of the county.
9 more New Mexico counties have 1 to 9 tested wells for nitrate, too few to rate.
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Where to get your well tested for nitrate in New Mexico
A lab New Mexico certifies
Ask for nitrate 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 nitrate.
Compare kitsKeep reading about wells in New Mexico
- Well water testing in New Mexico: how to get tested and what turns up statewide
- Nitrate in well water: where it comes from, what it does and how to remove it
- Arsenic 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 nitrate in New Mexico
Is there nitrate in New Mexico well water?
Nitrate is widespread, over the limit in 15% or more of tested wells, in 2 of the 14 New Mexico counties with 10 or more tested wells. Across New Mexico, about 1 in 10 tested wells had nitrate over the EPA limit of 10 mg/L (76 of 760). Across all tested wells in the US it's about 1 in 12. 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 nitrate 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 nitrate 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 mg/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.