Well water in McClain County, Oklahoma
In McClain County, 2% of 62 tested well samples exceeded the EPA limit for uranium (30 ug/L), based on public data from USGS Water Quality Portal.
The strongest signal is nitrate: 17% of 23 local samples were above the limit, too few samples to carry the headline but first on the test list below.
442 test results across 10 contaminants from at least 68 wells, 1948 to 2001; iron has the most at 68. Data refreshed September 15, 2026.
Compiled by Nick at Well Water Nerd from public records. How these pages are built
An estimated 13,872 people in McClain County get their drinking water from a private well, per USGS 2015 county water use. That is about 36% of residents.
Separately, the USGS national arsenic model estimates that <1% of the 13,872 people on private wells in McClain County draw water above 10 ug/L, from geology and well depth rather than local tests.
What individual samples found
Each row summarizes every public sample for that contaminant inside McClain 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 |
|---|---|---|---|---|---|---|
| Nitrate 1948 to 2001 | 23 | 91% | 2.3 | 150 | 10 mg/L EPA limit | |
| Uranium 1977 to 1978 | 62 | 92% | 3.3 | 74.9 | 30 ug/L EPA limit | |
| Arsenic 1977 to 1985 | 64 | 50% | 0.25 | 3.8 | 10 ug/L EPA limit | |
| Copper 1977 to 1985 | 62 | 55% | 0 | 0.12 | 1.3 mg/L EPA limit | |
| Fluoride 1948 to 1985 | 11 | 100% | 0.3 | 0.7 | 4 mg/L EPA limit | |
| Iron 1951 to 1985 | no limit | 68 | 13% | 0 | 1,170 | 300 ug/L nuisance level |
| Manganese 1951 to 1985 | no limit | 64 | 61% | 0 | 650 | 300 ug/L health guideline |
| Sodium 1951 to 1985 | no limit | 63 | 100% | 54.7 | 705 | 20 mg/L health guideline |
| Chloride 1948 to 1985 | no limit | 23 | 100% | 29 | 520 | 250 mg/L nuisance level |
Sampled fewer than 10 times, too few to summarize: Lead (2).
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 nitrate (17% of 23 samples) and uranium (2% of 62 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.
Manganese and Chloride 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 McClain County
- 1Nitrate17% of 23 local samples were above the limit.
- 2Uranium2% of 62 local samples were above the limit.
- 3Coliform bacteriaRecommended for every private well, every year.
- 4FluorideDetected in 100% of local samples.
- 5ChlorideDetected in 100% of local samples.
- 6ManganeseDetected in 61% of local samples.
- 7CopperDetected in 55% of local samples.
- 8Volatile organic compounds (VOCs)1 hazardous waste site on record locally.
- 9Metals panel1 hazardous waste site on record locally.
Test your McClain County well for nitrate, uranium and coliform bacteria
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 Oklahoma: certified labs, state programs and prices.
Already have results back? Get your lab report read against the McClain County numbers, $29. Every line explained, ranked by what matters, with the fix for each.
Wells in McClain County
2,096 domestic wells in McClain County are on record with the state since 1982. the typical well is 140 feet deep (one in ten goes past 200 feet).
In a typical McClain County well, the median yield is 12 gallons per minute, 8% of wells yield under 3 gallons per minute and usually need a storage tank.
Find your own well's report
The state keeps the driller's report for most wells drilled since 1984. It tells you how deep your well is, where bedrock starts, and how much water it makes, which decides what treatment can work.
- Open OWRB well log search and choose Water Well.
- It lists depth, first water, yield and the driller.
Oklahoma has required well logs since 1972.
The rock under McClain County
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 county centroid. A single well can sit in a different unit, especially near a boundary.
Official help in Oklahoma
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.
- Technical Assistance (private citizen well water testing), Oklahoma DEQ
- Laboratory Accreditation, Oklahoma DEQ
Contamination sources on record in McClain County
Oklahoma DEQ land sites records 1 hazardous waste site in McClain County, among 2 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
- hazardous waste siteSolvents, degreasers and metals from industrial sites can travel far in fractured bedrock.
- 1
- lined landfill or transfer facility
Treatment that fits the local profile
Nitrate
Point-of-use reverse osmosis; Anion exchange; Distillation
Uranium
Point-of-use reverse osmosis; Anion exchange; Whole-house anion exchange
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 nitrate
Under-sink reverse osmosis system
under-sink or countertop, about $300
Look for NSF/ANSI 58 certification listing the contaminant you need removed.
For nitrate
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 uranium
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.
Free, no obligation
Get on the list for a free in-home water test in McClain County
No water treatment company serves McClain 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 McClain County, and you get an email naming it first.
Common questions
How deep are wells in McClain County?
The typical domestic well in McClain County is 140 feet deep, based on 2,096 wells reported to the state since 1982. One in ten is deeper than 200 feet.
Is there arsenic in well water in McClain County?
Arsenic was detected in 50% of 64 public well samples in McClain County, and 0% 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 often should I test a private well in McClain 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 McClain 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 Oklahoma dataset as CSV, every county and town, with the sources named.
Sources
- USGS Water Quality Portal: 442 samples in McClain 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 13,872 people on private wells in McClain 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.
- Oklahoma OWRB reported well logs: 2,409 well records in McClain County, 2,096 domestic. Well completion reports filed with the Oklahoma Water Resources Board, located by public land survey. Only aggregates are shown; owner names and addresses are never stored. Retrieved .
- Oklahoma DEQ land sites: 2 regulated sites located in McClain County. Superfund sites, voluntary cleanup sites and solid waste facilities from the Oklahoma Department of Environmental Quality. 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.