Well water in El Paso County, Texas
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Testing recommended
tested well samples in El Paso County exceeded the EPA limit for arsenic (10 ug/L), based on public data from USGS Water Quality Portal and Texas Water Development Board Groundwater Database.
3,465 test results across 13 contaminants from at least 199 wells, 1952 to 2016; nitrate has the most at 774. Data refreshed September 15, 2026.
Compiled by Nick at Well Water Nerd from public records. How these pages are built
TWDB samples an ambient monitoring network of wells on a rotation, so these describe aquifers, not a survey of homeowners' tests.
An estimated 16,258 people in El Paso 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 14% of the 16,258 people on private wells in El Paso County draw water above 10 ug/L (the model's range is 12% to 17%), from geology and well depth rather than local tests.
What individual samples found
Each row summarizes every public sample for that contaminant inside El Paso 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 1995 to 2016 | 167 | 93% | 4 | 29 | 10 ug/L EPA limit | |
| Nitrate 1974 to 2016 | 774 | 80% | 1.6 | 48 | 10 mg/L EPA limit | |
| Fluoride 1952 to 2016 | 520 | 100% | 0.6 | 2.1 | 4 mg/L EPA limit | |
| Lead 1984 to 2016 | 208 | 32% | 0 | 10 | 15 ug/L EPA limit | |
| Copper 1992 to 2016 | 190 | 34% | 0 | 0.02 | 1.3 mg/L EPA limit | |
| Uranium 1995 to 2016 | 59 | 86% | 1.97 | 16 | 30 ug/L EPA limit | |
| Radium (226 + 228) 2003 to 2014 | 16 | 88% | 0.365 | 0.6 | 5 pCi/L EPA limit | |
| Chloride 1952 to 2016 | no limit | 543 | 100% | 160 | 4,000 | 250 mg/L nuisance level |
| Sodium 1952 to 2016 | no limit | 521 | 100% | 140 | 3,400 | 20 mg/L health guideline |
| Iron 1952 to 2016 | no limit | 235 | 69% | 12.1 | 4,120 | 300 ug/L nuisance level |
| Manganese 1977 to 2016 | no limit | 206 | 78% | 10.2 | 1,600 | 300 ug/L health guideline |
| Radon 1995 to 2014 | no limit | 18 | 100% | 296 | 890 | 2,000 pCi/L health guideline |
Sampled fewer than 10 times, too few to summarize: E. coli (8).
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 | 6%572 samples | 4%136 samples | 5%66 samples | n/a |
| Fluoride | 0%415 samples | 0%72 samples | 0%33 samples | n/a |
| Lead | 0%108 samples | 0%67 samples | 0%33 samples | n/a |
| Copper | 0%90 samples | 0%67 samples | 0%33 samples | n/a |
| Arsenic | 6%68 samples | 18%66 samples | 30%33 samples | n/a |
| Uranium | 0%15 samples | 0%11 samples | 0%33 samples | n/a |
Arsenic above the limit in El Paso County rose from 18% of 66 samples in the 2000s to 30% of 33 in the 2010s.
Nitrate, fluoride, lead, copper 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 (16% of 167 samples) and nitrate (5% of 774 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 El Paso County
- 1Arsenic16% of 167 local samples were above the limit.
- 2Nitrate5% of 774 local samples were above the limit.
- 3RadonMedian local reading is 296 pCi/L.
- 4E. coliAbove the limit in 1 of 8 local samples; too few to quote a rate.
- 5ChlorideDetected in 100% of local samples.
- 6FluorideDetected in 100% of local samples.
- 7ManganeseDetected in 78% of local samples.
- 8Volatile organic compounds (VOCs)600 leaking underground storage tank sites on record locally.
- 9Metals panel2 hazardous waste sites on record locally.
Test your El Paso County well for arsenic, nitrate and radon
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 Texas: certified labs, state programs and prices.
Already have results back? Get your lab report read against the El Paso County numbers, $29. Every line explained, ranked by what matters, with the fix for each.
The rock under El Paso 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 Texas
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, Texas Groundwater Protection Committee
- Environmental Laboratory (NELAP) Accreditation, TCEQ
Contamination sources on record in El Paso County
TCEQ records 600 leaking underground storage tank sites and 2 hazardous waste sites in El Paso County, among 626 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.
- 600
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 2
- hazardous waste sitesSolvents, degreasers and metals from industrial sites can travel far in fractured bedrock.
- 24
- 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
Nitrate
Point-of-use reverse osmosis; Anion exchange; Distillation
Chloride
Point-of-use reverse osmosis; Distillation
Manganese
Oxidizing filter (greensand, birm) whole-house; Water softener (low levels); Point-of-use reverse osmosis
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 manganese
Iron and manganese oxidizing filter
whole-house, at the point of entry, about $1,800
Air-injection or greensand media; fixes staining at the source.
Free, no obligation
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Common questions
Is there arsenic in well water in El Paso County?
Arsenic was detected in 93% of 167 public well samples in El Paso County, and 16% 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 El Paso County?
The median radon level across 18 public samples in El Paso County was 296 pCi/L, with a high of 890 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.
How often should I test a private well in El Paso 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 El Paso 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 Texas dataset as CSV, every county and town, with the sources named.
Sources
- USGS Water Quality Portal: 3,363 samples in El Paso 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.
- Texas Water Development Board Groundwater Database: 102 samples in El Paso County. Water quality samples from the Texas Water Development Board Groundwater Database, collected by TWDB, groundwater conservation districts and cooperators. Retrieved September 9, 2026.
- USGS national arsenic model (Ayotte 2017): estimated share of 16,258 people on private wells in El Paso 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.
- TCEQ regulated sites: 626 regulated sites located in El Paso County. Leaking petroleum storage tank sites, state Superfund sites and municipal solid waste landfills from the Texas Commission on Environmental Quality. Retrieved September 9, 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.