Well water in New Mexico
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Testing recommended
tested well samples in New Mexico exceeded the EPA limit for radium (226 + 228) (5 pCi/L), based on public data from USGS Water Quality Portal.
71,844 test results across 15 contaminants from at least 7,705 wells, 1906 to 2026; chloride has the most at 15,174. Data refreshed September 15, 2026.
Compiled by Nick at Well Water Nerd from public records. How these pages are built
An estimated 292,165 people in New Mexico get their drinking water from a private well, per USGS 2015 county water use.
Separately, the USGS national arsenic model estimates that 11% of the 292,165 people on private wells in New Mexico draw water above 10 ug/L (the model's range is 8% to 13%), from geology and well depth rather than local tests.
What individual samples found
Each row summarizes every public sample for that contaminant inside New Mexico. Above limit means above the EPA maximum contaminant level; where EPA has no enforceable limit, the row shows a health guideline or nuisance level instead.
| Contaminant | Above limit | Samples | Detected | Median | Highest | Limit |
|---|---|---|---|---|---|---|
| Radium (226 + 228) 1958 to 2021 | 525 | 81% | 0.16 | 510 | 5 pCi/L EPA limit | |
| Arsenic 1957 to 2026 | 3,835 | 77% | 1.1 | 1,100 | 10 ug/L EPA limit | |
| Nitrate 1924 to 2026 | 12,256 | 89% | 1.2 | 564 | 10 mg/L EPA limit | |
| Uranium 1952 to 2026 | 1,806 | 95% | 2.85 | 2,800 | 30 ug/L EPA limit | |
| Fluoride 1906 to 2026 | 10,366 | 97% | 0.7 | 3,980 | 4 mg/L EPA limit | |
| PFOA 2019 to 2026 | 394 | 6% | 0 | 72 | 4 ng/L EPA limit | |
| Lead 1954 to 2026 | 3,535 | 46% | 0 | 340,000 | 15 ug/L EPA limit | |
| E. coli 2005 to 2017 | 112 | 2% | 0 | 2 | 0 MPN/100mL EPA limit | |
| PFOS 2019 to 2026 | 394 | 10% | 0 | 1,300 | 4 ng/L EPA limit | |
| Copper 1906 to 2026 | 2,813 | 60% | 0 | 190 | 1.3 mg/L EPA limit | |
| Chloride 1906 to 2026 | no limit | 15,174 | 100% | 46 | 290,000 | 250 mg/L nuisance level |
| Sodium 1906 to 2026 | no limit | 8,202 | 100% | 75 | 130,000 | 20 mg/L health guideline |
| Iron 1924 to 2026 | no limit | 7,041 | 73% | 20 | 6,100,000 | 300 ug/L nuisance level |
| Manganese 1933 to 2026 | no limit | 5,157 | 79% | 10 | 340,000 | 300 ug/L health guideline |
| Radon 1993 to 2021 | no limit | 234 | 99% | 340 | 17,500 | 2,000 pCi/L health guideline |
Over time
Share of samples above the limit by period. A cell needs ten samples to show; a comparison needs twenty in each period. Later periods sample fewer wells, and often the ones already known to have a problem.
| Contaminant | before 2000 | 2000s | 2010s | 2020s |
|---|---|---|---|---|
| Nitrate | 11%8,821 samples | 12%2,104 samples | 10%1,044 samples | 5%287 samples |
| Fluoride | 6%7,149 samples | 22%1,699 samples | 2%895 samples | <1%623 samples |
| Arsenic | 12%1,692 samples | 12%1,082 samples | 16%680 samples | 4%381 samples |
| Lead | 5%1,490 samples | <1%1,037 samples | 0%657 samples | 1%351 samples |
| Copper | 1%1,186 samples | 0%600 samples | 0%657 samples | 0%370 samples |
| Uranium | 6%537 samples | 15%331 samples | 9%683 samples | 4%255 samples |
Nitrate above the limit in New Mexico fell from 10% of 1044 samples in the 2010s to 5% of 287 in the 2020s.
Arsenic above the limit in New Mexico fell from 16% of 680 samples in the 2010s to 4% of 381 in the 2020s.
Uranium above the limit in New Mexico fell from 9% of 683 samples in the 2010s to 4% of 255 in the 2020s.
Fluoride, lead, copper have held within a few points between the two most recent periods with enough samples.
What this means
The contaminants most often above their limit here are radium (226 + 228) (14% of 525 samples), arsenic (12% of 3,835 samples), and nitrate (11% of 12,256 samples). A well next door can differ sharply from yours because bedrock fractures, well depth and plumbing all matter, so these rates describe the area, not your tap.
Chloride, Iron, and Manganese are widespread in local groundwater. They are mainly a staining and taste problem, but high manganese also carries a health advisory for infants.
What to test for in New Mexico
- 1Radium (226 + 228)14% of 525 local samples were above the limit.
- 2Arsenic12% of 3,835 local samples were above the limit.
- 3Nitrate11% of 12,256 local samples were above the limit.
- 4Uranium8% of 1,806 local samples were above the limit.
- 5Fluoride8% of 10,366 local samples were above the limit.
- 6PFOA3% of 394 local samples were above the limit.
- 7Lead2% of 3,535 local samples were above the limit.
Test your New Mexico well for radium (226 + 228), arsenic and nitrate
Certified lab analysis of your own tap water, bottles and prepaid return shipping included. The Essential well panel covers arsenic, uranium, nitrate, lead, copper, manganese, iron, sodium and bacteria; radon and PFAS are add-ons.
Order the Tap Score well water test kit, from $209Already tested? Upload the report
Just want bacteria checked first? Tap Score coliform and E. coli test, $99. Coliform and E. coli are the tests every well needs every year.
Want a quick look before paying for a lab? Home well water test strips on Amazon check hardness, iron, pH and nitrate in minutes. They are a screen, not a result: arsenic, bacteria, uranium and PFAS need a certified lab.
Affiliate links: the merchant pays us a commission and the price is the same for you. It does not change what the data above says. As an Amazon Associate we earn from qualifying purchases.
Where to get a well tested in New Mexico: certified labs, state programs and prices.
Already have results back? Get your lab report read against the New Mexico numbers, $29. Every line explained, ranked by what matters, with the fix for each.
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Send me the New Mexico report
The numbers above, which tests to order and where, and the treatment that fits the local profile, in one email.
The rock under New Mexico
Not a principal aquifer
The USGS map places this area outside any principal aquifer, which usually means wells here draw from fractured bedrock or thin local deposits rather than a large regional aquifer. Bedrock wells of that kind are where arsenic, radon and uranium turn up, and yields vary from well to well.
Classification from the USGS Principal Aquifers of the United States (national map, 2003 edition, GIS release 2015), read at the state centroid. A single well can sit in a different unit, especially near a boundary.
Official help in New Mexico
Two places to start that are not selling anything: the state program that answers private well questions, and its list of labs certified to run drinking water tests. A certified lab is the difference between a result you can act on and a number.
- Private Wells, NMED
- Laboratory Certification, NMED
Contamination sources on record in New Mexico
NMED storage tank facilities and landfills records 1,354 regulated sites in New Mexico, among 1,354 regulated sites in total. Groundwater does not follow property lines, so a well within a few hundred feet of one of these is worth testing for what that site could release.
- 1,329
- registered underground storage tank sitesRegistered tanks are regulated and inspected; they matter most when they are old or near a shallow well.
- 25
- lined landfills and transfer facilities
Treatment that fits the local profile
Radium (226 + 228)
Water softener (cation exchange); Point-of-use reverse osmosis
Arsenic
Point-of-use reverse osmosis; Adsorptive media (iron-based) whole-house; Anion exchange
Nitrate
Point-of-use reverse osmosis; Anion exchange; Distillation
Uranium
Point-of-use reverse osmosis; Anion exchange; Whole-house anion exchange
Fluoride
Point-of-use reverse osmosis; Activated alumina; Distillation
Systems we would look at first
Some links below are affiliate links. If you buy through one, the merchant pays us a commission at no extra cost to you. It does not change which products we list or what the data says.
For radium (226 + 228)
Under-sink reverse osmosis system
under-sink or countertop, about $300
Look for NSF/ANSI 58 certification listing the contaminant you need removed.
For arsenic
Aquasana SmartFlow reverse osmosis
under-sink or countertop, about $225
Certified to NSF/ANSI 58 and 53 to reduce arsenic (96%, pentavalent), fluoride (90%), lead (99%), nitrate, nitrite and PFOA/PFOS at the kitchen tap, with a remineralizer.
For arsenic
Whole-house arsenic and uranium filter
whole-house, at the point of entry, about $2,500
Adsorptive iron-based media; sized to your well yield.
For PFOA
Aquasana Claryum 3-Stage under-sink filter
under-sink or countertop, about $175
Certified to NSF/ANSI 53 to reduce 99% of lead and 99.7% of PFOA and PFOS at the tap. Not a fix for arsenic, nitrate or bacteria.
For PFOA
Whole-house PFAS carbon system
whole-house, at the point of entry, about $3,000
Granular activated carbon certified to NSF/ANSI 53 for PFOA and PFOS; replace media on schedule.
For PFOA
Aquasana HealthShield whole-house filter
whole-house, at the point of entry, about $2,099
Whole-house carbon system the maker certifies to reduce PFAS (PFOA and PFOS) and VOCs at every tap; a UV option adds bacteria protection.
Common questions
Is there arsenic in well water in New Mexico?
Arsenic was detected in 77% of 3,835 public well samples in New Mexico, and 12% were above the EPA limit of 10 ug/L. Arsenic has no taste or smell; a lab test is the only way to know your level.
How high is radon in well water in New Mexico?
The median radon level across 234 public samples in New Mexico was 340 pCi/L, with a high of 17,500 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.
How often should I test a private well in New Mexico?
Test for bacteria and nitrate every year. Test once for arsenic, uranium, radon, fluoride, manganese and PFAS, then again every three to five years or after any change in taste, color, or plumbing.
Counties in New Mexico
- Bernalillo19% arsenic
- Catron9% arsenic
- Chaves8% nitrate
- Cibola39% uranium
- ColfaxUSGS estimate
- Curry1% arsenic
- De Baca61 samples
- Doña Ana25% fluoride
- Eddy75% radium (226 + 228)
- Grant15% nitrate
- GuadalupeUSGS estimate
- Harding10% nitrate
- Hidalgo21% fluoride
- Lea2% fluoride
- Lincoln0% lead
- Los Alamos18% nitrate
- Luna30% arsenic
- McKinley18% radium (226 + 228)
- MoraUSGS estimate
- Otero38% arsenic
- Quay32 samples
- Rio Arriba28% arsenic
- Roosevelt11% fluoride
- Sandoval34% arsenic
- San Juan8% uranium
- San Miguel43 samples
- Santa Fe12% nitrate
- Sierra12% uranium
- Socorro24% arsenic
- Taos3% fluoride
- Torrance14% nitrate
- Union15% nitrate
- Valencia32% arsenic
Want the numbers themselves? Download the New Mexico dataset as CSV, every county and town, with the sources named.
Sources
- USGS Water Quality Portal: 71,844 samples in New Mexico. Data from the Water Quality Portal, a service of USGS, EPA and USDA; groundwater samples collected by USGS and cooperators. Retrieved September 3, 2026.
- USGS national arsenic model (Ayotte 2017): estimated share of 292,165 people on private wells in New Mexico above 10 ug/L of arsenic, from geology, well depth and land use. County estimates of domestic well users with arsenic above 10 ug/L from the USGS national logistic regression model (Ayotte, Medalie and Qi, 2017), with private well population from the USGS 2015 county water-use compilation (Dieter and others, 2018). Retrieved September 15, 2026.
- NMED storage tank facilities and landfills: 1,354 regulated sites located in New Mexico. Underground storage tank facilities and permitted landfills from the New Mexico Environment Department. Retrieved September 18, 2026.
Non-detects count as samples and are treated as zero when computing medians. Exactly at the limit counts as not above it. A sample belongs to the town containing the well's reported coordinates.