Well water in Bernalillo County, New Mexico
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Testing strongly recommended
tested well samples in Bernalillo County exceeded the EPA limit for arsenic (10 ug/L), based on public data from USGS Water Quality Portal.
14,435 test results across 15 contaminants from at least 701 wells, 1944 to 2025; nitrate has the most at 3,626. Data refreshed September 15, 2026.
Compiled by Nick at Well Water Nerd from public records. How these pages are built
An estimated 11,663 people in Bernalillo County get their drinking water from a private well, per USGS 2015 county water use. That is about 2% of residents.
Separately, the USGS national arsenic model estimates that 21% of the 11,663 people on private wells in Bernalillo County draw water above 10 ug/L (the model's range is 16% to 28%), from geology and well depth rather than local tests.
What individual samples found
Each row summarizes every public sample for that contaminant inside Bernalillo County. 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 |
|---|---|---|---|---|---|---|
| Arsenic 1972 to 2025 | 839 | 85% | 2.4 | 70 | 10 ug/L EPA limit | |
| PFOA 2020 to 2025 | 23 | 22% | 0 | 6.7 | 4 ng/L EPA limit | |
| Nitrate 1944 to 2025 | 3,626 | 80% | 1 | 529 | 10 mg/L EPA limit | |
| PFOS 2020 to 2025 | 23 | 30% | 0 | 5.1 | 4 ng/L EPA limit | |
| Fluoride 1945 to 2025 | 1,440 | 98% | 0.41 | 11 | 4 mg/L EPA limit | |
| Uranium 1978 to 2021 | 559 | 99% | 2.03 | 89 | 30 ug/L EPA limit | |
| Copper 1972 to 2025 | 670 | 47% | 0 | 0.02 | 1.3 mg/L EPA limit | |
| Lead 1972 to 2025 | 669 | 41% | 0 | 10 | 15 ug/L EPA limit | |
| Radium (226 + 228) 2007 to 2016 | 108 | 62% | 0.042 | 0.96 | 5 pCi/L EPA limit | |
| E. coli 2005 to 2014 | 30 | 0% | 0 | 0 | 0 MPN/100mL EPA limit | |
| Chloride 1944 to 2025 | no limit | 2,231 | 100% | 39.4 | 780 | 250 mg/L nuisance level |
| Iron 1944 to 2025 | no limit | 1,781 | 66% | 10 | 27,000 | 300 ug/L nuisance level |
| Sodium 1953 to 2025 | no limit | 1,216 | 100% | 29.6 | 1,000 | 20 mg/L health guideline |
| Manganese 1963 to 2025 | no limit | 1,167 | 80% | 6.69 | 4,000 | 300 ug/L health guideline |
| Radon 1993 to 2015 | no limit | 53 | 100% | 300 | 1,010 | 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 | 14%2,661 samples | 6%275 samples | 12%650 samples | 5%40 samples |
| Fluoride | 2%646 samples | <1%165 samples | 0%378 samples | <1%251 samples |
| Arsenic | 14%290 samples | 33%151 samples | 16%377 samples | 29%21 samples |
| Copper | 0%159 samples | 0%113 samples | 0%377 samples | 0%21 samples |
| Lead | 0%165 samples | 0%106 samples | 0%377 samples | 0%21 samples |
| Uranium | 7%41 samples | <1%125 samples | <1%376 samples | 0%17 samples |
Nitrate above the limit in Bernalillo County fell from 12% of 650 samples in the 2010s to 5% of 40 in the 2020s.
Arsenic above the limit in Bernalillo County rose from 16% of 377 samples in the 2010s to 29% of 21 in the 2020s.
Fluoride, copper, lead, uranium have held within a few points between the two most recent periods with enough samples.
Closer than the county
See the sampled wells near your address
The same records, drawn around one point: which wells within a few miles were sampled and what they found, how deep the wells next to you were drilled, and any leaking tank or cleanup site within a mile.
Check my addressWhat this means
The contaminants most often above their limit here are arsenic (19% of 839 samples), pfoa (17% of 23 samples), and nitrate (13% of 3,626 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 Bernalillo County
- 1Arsenic19% of 839 local samples were above the limit.
- 2PFOA17% of 23 local samples were above the limit.
- 3Nitrate13% of 3,626 local samples were above the limit.
- 4PFOS4% of 23 local samples were above the limit.
- 5Fluoride1% of 1,440 local samples were above the limit.
- 6Uranium<1% of 559 local samples were above the limit.
- 7Coliform bacteriaRecommended for every private well, every year.
Test your Bernalillo County well for arsenic, PFOA 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 Bernalillo County numbers, $29. Every line explained, ranked by what matters, with the fix for each.
The rock under Bernalillo County
Rio Grande aquifer system
Unconsolidated sand and gravel. Wells in sand and gravel are usually shallow and productive, and they recharge quickly from the surface. That makes them the most exposed to nitrate, bacteria and anything spilled nearby, and the least likely to carry arsenic or radon from the rock.
Classification from the USGS Principal Aquifers of the United States (national map, 2003 edition, GIS release 2015), read at the county 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 Bernalillo County
NMED storage tank facilities and landfills records 316 regulated sites in Bernalillo County, among 316 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.
- 314
- registered underground storage tank sitesRegistered tanks are regulated and inspected; they matter most when they are old or near a shallow well.
- 2
- lined landfills and transfer facilities
Treatment that fits the local profile
Arsenic
Point-of-use reverse osmosis; Adsorptive media (iron-based) whole-house; Anion exchange
PFOA
Granular activated carbon whole-house; Point-of-use reverse osmosis; Anion exchange
Nitrate
Point-of-use reverse osmosis; Anion exchange; Distillation
PFOS
Granular activated carbon whole-house; Point-of-use reverse osmosis; 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 arsenic
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
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 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 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.
Free, no obligation
Get on the list for a free in-home water test in Bernalillo County
No water treatment company serves Bernalillo County through Well Water Nerd yet. We are signing licensed companies on county by county: they test at your tap for free, walk you through the numbers, and quote treatment only if something needs fixing. Leave your details and you are first in line. Nothing is shared until a company joins for Bernalillo County, and you get an email naming it first.
Common questions
Is there arsenic in well water in Bernalillo County?
Arsenic was detected in 85% of 839 public well samples in Bernalillo County, and 19% 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 Bernalillo County?
The median radon level across 53 public samples in Bernalillo County was 300 pCi/L, with a high of 1,010 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.
How often should I test a private well in Bernalillo County?
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 near Bernalillo County
Closest first. Groundwater does not stop at a line on a map, so the next county over is a fair second opinion.
Want the numbers themselves? Download the New Mexico dataset as CSV, every county and town, with the sources named.
Sources
- USGS Water Quality Portal: 14,435 samples in Bernalillo County. 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 11,663 people on private wells in Bernalillo County 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: 316 regulated sites located in Bernalillo County. 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.