How Often Should You Test Well Water in Oklahoma?
The Answer Nobody Loves: At Least Once a Year
You're standing in your kitchen, filling a glass of water from the tap, and it looks fine. Smells fine. Tastes fine. So why would you pay someone to tell you what you already know?
Because here's the thing about well water — and I spent enough years in nursing to know this pattern by heart — the stuff that can hurt you is almost never the stuff you can see, smell, or taste. Bacteria don't announce themselves. Nitrates don't leave a calling card. By the time your water looks or tastes wrong, you've usually been drinking the problem for weeks or months.
It's the same principle behind routine bloodwork. Your doctor doesn't wait for you to turn yellow before checking your liver enzymes. We test before symptoms appear because the whole point is to catch problems when they're still manageable — not when they're already causing damage.
Your private well gets the same logic. Test annually. Minimum.
The Bottom Line: Test your well water annually for bacteria (coliform), nitrates, and basic chemistry (pH, conductivity). Test more frequently after flooding, if you notice any changes in taste, odor, or color, or if infants or pregnant women are in the household. Unlike municipal water, nobody is testing your well for you.
Why Private Wells Are Different
If you're on city water in Oklahoma City, Norman, or Edmond, your water utility tests constantly. They're required to. The EPA has regulations, there's monitoring, there are reports. You can look up your city's Consumer Confidence Report and see exactly what they found.
Private well? None of that applies to you.
The Oklahoma Department of Environmental Quality doesn't regulate private residential wells. The EPA doesn't either. Your well is your responsibility — from the aquifer to the glass. Nobody is monitoring it. Nobody is alerting you to problems. Nobody is fixing anything for you.
I say this not to scare you, but because I'm amazed at how many people don't know it. They assume that because their water comes from the ground — you know, "natural" — it must be fine. Or they assume someone is testing it somewhere. Neither is true.
"I've tested wells that looked pristine — nice property, well-maintained wellhead, tidy pump house — and the results came back with coliform bacteria levels that made the water unsafe to drink. The well didn't look sick. But the water was."
The Annual Testing Baseline
The ODEQ recommends that private well owners test annually for the essentials — the things that are most likely to go wrong and most dangerous when they do:
Total Coliform Bacteria
The sentinel test. Coliform bacteria indicate that surface water, sewage, or animal waste may be reaching your well. If coliform shows up, we test for E. coli next — because E. coli means fecal contamination, and that's a "stop drinking this water right now" situation.
Nitrates / Nitrites
Oklahoma is an agricultural state. Fertilizer, livestock waste, and septic leachate all contribute nitrates to groundwater. At levels above 10 mg/L, nitrates cause "blue baby syndrome" — a condition where an infant's blood loses the ability to carry oxygen. As a nurse, I can tell you that's as scary as it sounds.
pH
pH tells you whether your water is corrosive. Acidic water (low pH) eats copper pipes and can leach lead from solder joints. It's not just a chemistry lesson — it's a "what is your plumbing dissolving into your drinking water" question.
Total Dissolved Solids (TDS) / Conductivity
A general indicator of mineral content. Not dangerous by itself, but a spike in TDS compared to your baseline can signal that something has changed in your aquifer or well.
That's it for the baseline. Four tests, once a year. It's your annual physical for your water supply — and it catches the most common and most dangerous problems.
When to Test More Often
Life doesn't always follow schedules, though. Here are the situations where annual testing isn't enough and you should test immediately:
After Flooding or Heavy Rain
Oklahoma's storm season is no joke. When floodwater breaches your well — whether through a damaged casing, a compromised seal, or just sheer volume of surface water saturating the ground — your well becomes a pipe that's collecting whatever the flood carried. And Oklahoma floods carry agricultural runoff, sewage overflow, and whatever was sitting on the surface of every property upstream of yours.
Test within a few days of significant flooding. Specifically for bacteria. Don't wait for the annual cycle.
When Your Water Changes
This one should be intuitive but I'll say it anyway: if your water starts tasting different (metallic, salty, bitter), smelling different (rotten eggs, chemical), or looking different (cloudy, discolored, sediment) — test. Don't just run it for a minute and decide it's probably fine. Changes mean something has changed, and the list of possibilities ranges from "annoying but harmless" to "stop drinking this immediately."
Infants or Pregnant Women in the Home
Nitrates are particularly dangerous for babies under six months because their digestive systems convert nitrate to nitrite more efficiently than adults. Nitrite interferes with hemoglobin's ability to carry oxygen — that's blue baby syndrome. I've seen what oxygen deprivation does to developing brains, and once is enough to take nitrate testing very seriously.
If you're expecting or have an infant, test for nitrates before the baby arrives and periodically during infancy. This is not optional. This is the test I'd do if it were my grandkid.
After Well Work
Any time the well has been opened up — pump replacement, casing repairs, any maintenance that exposed the wellbore to the atmosphere — test before drinking. Opening a well is like opening a wound. You've introduced the possibility of contamination, and you need to verify sterility before proceeding.
That's a nursing analogy I didn't even have to force. It's just how wells work.
Nearby Land Use Changes
New feedlot goes in a mile from your property? Someone installs a septic system uphill from your well? Oil and gas activity starts nearby? Industrial development? All of these are reasons to increase your monitoring frequency. Groundwater contamination travels slowly — sometimes it takes months or years to reach your well from a new source. Ongoing monitoring catches the contamination as it arrives rather than after your family has been drinking it.
The Every-Three-Year Tests
Beyond the annual basics, the EPA recommends testing every three years for substances that change slowly and cause mostly aesthetic issues (with a few health exceptions):
| Contaminant | Why It Matters | Oklahoma Relevance |
|---|---|---|
| Sulfate | Causes laxative effects at high levels | Common in some Oklahoma groundwater formations |
| Chloride | Can indicate saltwater intrusion | A real concern near oil and gas operations |
| Iron & Manganese | Staining, metallic taste | Very common in Oklahoma aquifers — the red clay state earns its name |
| Hardness | Scale buildup, soap effectiveness | Most Oklahoma wells have hard water — it's geology, not a problem |
| Corrosivity | Can leach lead and copper from plumbing | Important for homes with older pipes |
One-Time and Situational Tests
Some things you test once to establish a baseline, then only retest if conditions change:
- Lead — Test if your home has old plumbing or you've never tested. Lead comes from your pipes, not your aquifer, but it's still coming out of your tap
- Arsenic — Based on local geology. Some Oklahoma rock formations contain naturally occurring arsenic. One test tells you if it's an issue
- Pesticides — If you're near agricultural operations, a baseline test determines whether anything is reaching your aquifer
- VOCs — If a fuel spill, chemical leak, or industrial activity occurs near your property
- Radon — If your area shows elevated radon levels, dissolved radon can also appear in groundwater
- PFAS ("forever chemicals") — If you're near a military base, airport, or industrial site where firefighting foam was used. Read more about PFAS in Oklahoma water
Oklahoma-Specific Risks You Should Know About
Oklahoma isn't Iowa and it isn't California. Our specific geology, industry, and weather create a distinct risk profile for well water:
- Agricultural runoff — We're a farming and ranching state. Nitrates from fertilizer and animal waste are the most common contaminant I find in rural Oklahoma wells
- Oil and gas operations — Oklahoma has more than 300,000 documented oil and gas wells. Spills, leaks, produced water disposal, and legacy contamination from decades of extraction all threaten groundwater
- Seismic activity — Yes, the earthquakes. Oklahoma's induced seismicity can damage well casings, disrupt aquifer layers, and create new pathways for contaminants to reach groundwater. If your area has been experiencing tremors, your well's structural integrity deserves a second look
- Hard water — Not dangerous, but universal. Oklahoma's geology means calcium and magnesium are in virtually every aquifer. You'll probably want a softener, but you don't need to panic
- Clay soil drainage — Oklahoma's red clay doesn't filter water the way sandy soil does. During heavy rain, surface contaminants can reach shallow wells faster than you'd expect
The Records Trick: Keep every well water test result. Over time, your records create a baseline that makes trends visible. A gradual increase in nitrates over three years tells a different story than a sudden spike — and each requires a different response. Your well's medical history matters just as much as yours.
Where to Get Your Well Tested
You have several options in Oklahoma, and I'll tell you the pros and cons of each:
- Oklahoma DEQ State Environmental Laboratory — EPA-certified, reliable, limited test menu. Good for the basics
- OSU Extension offices — Sometimes offer free or low-cost screening events, especially for nitrates. Great if the timing works out
- Private laboratories — More comprehensive testing options. Make sure they're EPA-certified — if they're not, the results are decoration
- Environmental inspectors (like me) — I offer water testing as part of comprehensive property assessments. The advantage: I've collected thousands of samples and can tell you what the results mean in context, not just hand you a spreadsheet
The Perspective I'd Want If It Were My Well
I drink from a well. I test it. Annually. After storms. After any work on the system. Not because I'm paranoid — because I know what's in the ground in Oklahoma, and I'd rather know what's in my water than hope for the best.
Here's what I tell every well owner I work with: testing is the cheapest insurance you'll buy this year. A basic panel runs a fraction of what you'd spend on a single emergency vet visit, and it tells you whether the water your family drinks every day is actually safe.
You wouldn't skip your kid's annual checkup. Don't skip your well's.
When Was Your Well Last Tested?
Annual testing catches problems before they cause harm. I test wells across Oklahoma with clear results and context — not just numbers.
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