Well water in Ellis County, Oklahoma
1in3
Testing strongly recommended
tested well samples in Ellis County exceeded the EPA limit for nitrate (10 mg/L), based on public data from USGS Water Quality Portal.
277 test results across 11 contaminants from at least 38 wells, 1947 to 2013; nitrate has the most at 237. Data refreshed September 15, 2026.
Compiled by Nick at Well Water Nerd from public records. How these pages are built
An estimated 1,737 people in Ellis County get their drinking water from a private well, per USGS 2015 county water use. That is about 41% of residents.
Separately, the USGS national arsenic model estimates that 4% of the 1,737 people on private wells in Ellis County draw water above 10 ug/L (the model's range is 4% to 5%), from geology and well depth rather than local tests.
What individual samples found
Each row summarizes every public sample for that contaminant inside Ellis 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 1947 to 2013 | 237 | 100% | 4 | 197 | 10 mg/L EPA limit | |
| Chloride 1947 to 1999 | no limit | 23 | 100% | 34 | 155 | 250 mg/L nuisance level |
Sampled fewer than 10 times, too few to summarize: Fluoride (3), Lead (1), Arsenic (1), Copper (1), Uranium (1), Sodium (3), Manganese (3), Iron (3), Radon (1).
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 | 50%22 samples | 21%164 samples | 49%51 samples | n/a |
Nitrate above the limit in Ellis County rose from 21% of 164 samples in the 2000s to 49% of 51 in the 2010s.
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 (30% of 237 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 is widespread in local groundwater. It is mainly a staining and taste problem, but high manganese also carries a health advisory for infants.
What to test for in Ellis County
- 1Nitrate30% of 237 local samples were above the limit.
- 2Coliform bacteriaRecommended for every private well, every year.
- 3RadonMedian local reading is 270 pCi/L.
- 4FluorideDetected in 100% of local samples.
- 5ChlorideDetected in 100% of local samples.
Test your Ellis County well for nitrate, coliform bacteria 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 Oklahoma: certified labs, state programs and prices.
Already have results back? Get your lab report read against the Ellis County numbers, $29. Every line explained, ranked by what matters, with the fix for each.
Wells in Ellis County
478 domestic wells in Ellis County are on record with the state since 1974. the typical well is 200 feet deep (one in ten goes past 332 feet).
In a typical Ellis County well, the median yield is 60 gallons per minute, 1% 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 Ellis County
High Plains aquifer
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 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
Treatment that fits the local profile
Nitrate
Point-of-use reverse osmosis; Anion exchange; 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 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.
Free, no obligation
Get on the list for a free in-home water test in Ellis County
No water treatment company serves Ellis 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 Ellis County, and you get an email naming it first.
Common questions
How deep are wells in Ellis County?
The typical domestic well in Ellis County is 200 feet deep, based on 478 wells reported to the state since 1974. One in ten is deeper than 332 feet.
How often should I test a private well in Ellis 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 Ellis 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: 277 samples in Ellis 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 1,737 people on private wells in Ellis 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: 2,070 well records in Ellis County, 478 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 .
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.