Well water testing: what to test for, how often, and what it costs

If your water comes from a city utility, someone tests it for you and must meet federal limits. If it comes from your own well, nobody does. EPA puts it plainly: private wells aren’t regulated under the Safe Drinking Water Act or by most states, so the owner is responsible for the water’s safety¹. That’s around 15% of Americans, over 43 million people¹.

Clear, good-tasting water can still contain bacteria or nitrate. Testing is the only way to know, and it costs less than most people expect.

The four yearly basics

EPA and CDC both recommend testing a private well at least once a year for the same four things²³:

Test	Why it matters	EPA benchmark
Total coliform bacteria (and E. coli)	A positive result suggests disease-causing germs may be getting into the well	Goal is zero
Nitrate	High levels can make people sick, especially babies	10 mg/L (as nitrogen)
pH	Low pH means corrosive water that can pull metals like lead and copper from plumbing	6.5–8.5 (guideline)
Total dissolved solids (TDS)	Minerals and salts dissolved in the water; high levels cause deposits, staining and a salty taste	500 mg/L (guideline)

Limits are EPA's standards for public water systems. They don't legally apply to private wells, but they're the yardstick labs and health departments use.

The bacteria and nitrate explanations come from CDC³; the benchmarks from EPA’s primary and secondary drinking water standards⁴⁵.

Build your own test list

The four basics are the minimum. What else you should test depends on your household and what’s near your well. The planner below uses EPA’s own chart of situations and the tests that go with them², plus CDC’s advice for pregnancy and young children³.

Interactive tool

Well water test planner

Tick everything that applies. Tests marked “Test now” shouldn't wait for your next routine check.

What’s going on

Buying the home, a new well, or no test results on file Someone is pregnant, or a baby or young child lives here Flooding near the well, or the well or pump was just repaired The water suddenly looks, smells or tastes different Repeated stomach illness in the household

Near your well

Crop fields, livestock or heavy fertilizer use Septic systems close to the well, including your own Coal or other mining Gas or oil drilling Landfill, junkyard, factory, gas station or dry cleaner Buried fuel tanks, or a gasoline or fuel-oil smell Salty taste, seawater nearby, or a heavily salted road

Your water and plumbing

Plumbing that may contain lead (lead pipes are more likely in homes built before 1986) Corroded pipes, pinhole leaks, or treatment equipment that wears out fast Orange, brown, black or blue-green stains on fixtures or laundry Rotten-egg smell or an unpleasant taste Scale on fixtures, soap that won’t lather, or you’re choosing a softener Cloudy, frothy or colored water Radon found in your indoor air, or you live in a radon-prone area

Your test list

4 tests

The yearly basics every well owner should run.

• Also ask your state drinking water program which natural contaminants are common where you live: arsenic, uranium, radon, fluoride and manganese vary with the local rock.
• Use a state-certified lab. Your county health department may test for free or know who does.

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When to test right away

Don’t wait for the yearly test if²³:

• There’s been flooding near the well, or the ground around it has been disturbed by construction or nearby industry
• Any part of the well system was repaired or replaced
• The water’s taste, color or smell changes
• Someone in the home becomes pregnant, or a child starts living with you
• You hear of problems with wells or groundwater in your area

EPA also suggests testing more often than once a year if young children or elderly adults live with you, or someone is pregnant or nursing².

Tests to add for your area

Some contaminants come from the rock itself, not from anything nearby, and they vary a lot from place to place. CDC recommends asking your health department what else to test for where you live, mentioning volatile organic compounds, lead, arsenic, mercury, radium and pesticides³.

Lead deserves a test of its own. It usually comes from the plumbing, not the aquifer: EPA explains that lead gets into water when plumbing materials that contain it corrode, and that lead pipes are more likely in homes built before 1986. Even newer homes can have brass or chrome-plated brass faucets and lead solder⁶. EPA says there is no safe level of exposure and that young children, infants and fetuses are particularly vulnerable⁶.

How to get the water tested

1. Call your county or local health department first. EPA notes it may test private wells for free, and it knows the local problems².
2. Use a certified lab. EPA’s advice is to use only laboratories certified for drinking water testing². Your state health or drinking water department can tell you which labs are certified.
3. Use the lab’s bottles and follow its instructions to the letter. Timing matters: Penn State’s lab, for example, must receive bacteria samples within 30 hours of collection and can’t accept them on Fridays⁷.
4. Keep every report. Year-to-year changes are often more telling than a single result.

What testing costs

Prices vary by lab and state. Two public labs publish theirs, which gives a good idea of what to expect:

Lab	Test or package	Price
Penn State AASL	Standard: coliform, E. coli, pH, TDS	$60
Penn State AASL	Agriculture/Septic: standard + nitrate	$70
Penn State AASL	Corrosivity package + lead and copper	$125
Penn State AASL	Extensive: adds hardness, metals, lead, sodium, chloride, sulfate, nitrate and more	$220
Wisconsin SLH	Bacteria (total coliform and E. coli)	$35
Wisconsin SLH	Nitrate	$35
Wisconsin SLH	Homeowner package: bacteria, nitrate, nitrite, fluoride, metals screen, hardness, VOC and atrazine screens	$450

Penn State AASL and Wisconsin State Laboratory of Hygiene price lists, checked October 2026. Private labs and other states charge different amounts.

So the yearly basics cost roughly $60 to $70 at a public lab⁷⁸. A broad first-time panel, worth doing when you buy a house or have never tested, runs from about $220 to $450⁷⁸.

Reading your results

Your report lists each result next to a limit. These are the federal numbers labs usually compare against⁴⁵:

Contaminant	EPA number	Type
Total coliform bacteria	Goal: zero	Health
Nitrate (as N)	10 mg/L	Health
Nitrite (as N)	1 mg/L	Health
Arsenic	0.010 mg/L	Health
Uranium	0.030 mg/L	Health
Fluoride	4.0 mg/L (2.0 for tooth discoloration)	Health / guideline
Lead	Action level 0.015 mg/L (0.010 from Nov 1, 2027); goal zero	Health
Copper	Action level 1.3 mg/L	Health
Iron	0.3 mg/L	Guideline: rusty color, staining
Manganese	0.05 mg/L	Guideline: black staining, bitter taste
Sulfate	250 mg/L	Guideline: salty taste
Chloride	250 mg/L	Guideline: salty taste
Total dissolved solids	500 mg/L	Guideline: deposits, taste
pH	6.5–8.5	Guideline: corrosion or scale

Primary standards protect health and are legally binding for public systems. Secondary guidelines cover taste, odor, color and staining. Source: EPA, checked October 2026.

Hardness doesn’t appear in either EPA list⁵: it’s mostly a nuisance (scale, soap that won’t lather) and a question of comfort and appliances.

When a result is bad

• Coliform bacteria: switch to bottled or boiled water, then disinfect the well and test again. Our step-by-step guide to a positive coliform test explains what to do and how to find the source.
• E. coli or fecal coliform: stop drinking the water and contact your local health department for guidance⁹.
• Nitrate or bacteria, with a septic system in the yard: Penn State lists high nitrogen or bacteria in well water among the signs a septic system may be starting to fail, while noting that basic tests can’t confirm it on their own¹⁰. See how often to pump a septic tank for the warning signs.
• Iron or manganese above the guideline, or orange or black stains: see orange, brown or black stains from well water, including the stricter manganese limit for babies.
• A rotten-egg smell: usually hydrogen sulfide, a nuisance rather than a health problem. See why well water smells like rotten eggs to find the source.
• Anything else above a health limit: retest to confirm, then ask your health department about the source and the right treatment. Treatment depends entirely on the contaminant, so choose equipment from an independent lab result rather than a seller’s in-home test.

Well water test planner Tick what applies to your home and get the tests public health agencies suggest, and why.