Well Water Test Kits and Lab Tests: What to Test For and When a Kit Is Not Enough

A well water test kit from the hardware store can tell you something is worth checking. It cannot tell you your well is fine. For that you need a state-certified lab at least once a year for total coliform bacteria, nitrate, total dissolved solids and pH, which is what EPA advises, plus a wider panel chosen for where you live.

This page is part of our well water guide. It covers which tests you need and how often, what independent studies found about kits, what labs charge, and how to take a sample the lab will accept. WaterPlain has no lab and has not tested any kit. We report published evaluations, agency guidance and sellers’ own listings, and we earn nothing from any test you buy.

The short answer

• Every year: bacteria (total coliform and E. coli) and nitrate at a certified lab. EPA and CDC add pH and total dissolved solids (TDS).
• Once now, then every 3 to 5 years: a metals panel covering at least arsenic, lead, manganese and iron. Agencies differ on the interval, so this is our default.
• Only if your location calls for it: solvents and fuel compounds (VOCs), pesticides, radon, PFAS, and gas-drilling markers.
• A kit is fine for: hardness, a TDS reading, and a quick look between lab tests.
• A kit is not enough for: a baby or pregnancy in the home, repeat stomach illness, a flood or well repair, a fuel smell, a home sale, or any decision about lead, arsenic or nitrate.
• Example costs: $70 a year for bacteria and nitrate at Wisconsin’s state lab, free in nearly all Iowa counties, and about $200 to $400 for a broad mail-in lab kit.

Testing matters more on a well because nobody does it for you. EPA says private wells are not regulated under the Safe Drinking Water Act, and owners are responsible for their own water. In a USGS study of 2,100 domestic wells, about one in five had at least one contaminant above a human-health benchmark, most often metals, radionuclides or nitrate. USGS and CDC researchers later estimated that about 2.1 million people in the lower 48 states use domestic wells with predicted arsenic above 10 µg/L.

Kit or lab: which you need

Your situation	Use	Why
Routine yearly check	Certified lab: bacteria and nitrate at minimum	CDC recommends a state-certified lab for yearly testing
Baby in the home, pregnant, or planning to be	Certified lab: nitrate and lead first	Wisconsin DHS says to test both before the water is used by babies or anyone who is or may become pregnant
Repeat stomach illness in the household	Certified lab for coliform bacteria, and call your doctor and health department	EPA lists this as a reason to test. A strip gives no reassurance here
Flood, well repair or new pump	Certified lab for bacteria, after any disinfection	CDC and EPA both name these events
Fuel or chemical smell	No kit. Use bottled water and call the health department	CDC: boiling or disinfection will not make this water safe
Buying or selling a home	Certified lab, using the lab’s own bottles	Some states require it, and lenders may ask. See home sales
Choosing a softener or filter	Lab report for iron, manganese, hardness and pH	Treatment follows the numbers, and Penn State says to be cautious of results from uncertified labs or water treatment salespeople
Hardness only	Home kit is fine	Our hardness test kit guide covers the options. Feed the result into the softener sizing tool
Watching TDS between lab tests	Home meter is fine	A TDS meter shows drift, not what the dissolved material is
Curiosity, or a check between lab tests	Strip kit, as a screen	Follow up anything odd at a lab, and do not read a clean strip as an all-clear

What studies found about home kits

We found no federal program that certifies consumer water test kits. EPA itself says it cannot test home water and sends well owners to their state program or a certified lab. Emily Kumpel, senior author of the UMass Amherst study below, calls it “an unregulated space”. Four independent evaluations are worth knowing:

Evaluation	What was tested	What it found
UMass Amherst, 2025 (paper)	8 kits for iron, copper, manganese and fluoride, in deionized, tap and river water	No multi-parameter kit detected low iron. Three of four single-parameter kits did, though often too high or too low. At high iron, most multi-parameter kits read low. Many kits did well in deionized water and poorly in real water
Virginia Tech and others, 2021	16 lead kit brands	12 brands were unsuitable for drinking water, with detection limits of 5 to 20 mg/L. That is hundreds to more than a thousand times the 15 µg/L action level. Binary strips caught dissolved lead at relevant levels but missed particles
Washington State study, 2008	One nitrate strip, used by residents in 102 homes, against a lab	Moderate match (r = 0.72). Where nitrate was present, the lab read higher than the strip in 81% of homes. 7% of people struggled to tell the colors apart
San Francisco utility, 2018 to 2019	3 kit brands, over 400 tests on city tap water	Above 80% agreement with the lab on coliform, nitrate, nitrite and iron for all three. Mixed on lead and copper, with data quality problems in one brand. Below 60% on pH for two brands. Below 60% on hardness, which the utility blames on its very soft water; above 80% in harder water

Four things follow for a well owner.

1. A strip gives a color step, not a number. One strip kit listed at $7.49 for two tests prints its nitrate chart at 0, 2, 10, 20 and 50 ppm as nitrogen. A well at 7 sits between two blocks, and the next step up is the health benchmark. That is the range where you most need a number.
2. The errors in these studies often run the unsafe way. Strips that read low on nitrate and kits that read low on high iron both make water look better than it is.
3. Lead on a well is often in particles. In a Virginia study of 2,146 homeowner samples, almost 20% of first-draw samples were above 15 µg/L, and on average 47% of the lead in a tested subset was particulate. That is the form the strips missed. The samples came from homeowners who chose to test, so this is not a state average.
4. City-water results do not transfer. San Francisco’s kits were tested on treated tap water. A kit that agrees with a lab there tells you little about how it behaves in a well with iron, sulfur or high minerals. UMass found real water was where kits struggled.

Kumpel says kits “might be a good first cut”, and that is the right way to use them. None of the evaluations above covered arsenic, uranium, radon, VOCs or PFAS, so we know of no independent basis for trusting a home kit on those. Send them to a lab. If a home kit shows bacteria, switch to bottled water or another safe source until a lab has checked it.

The four ways to test

Option	Price seen	Good for	Limits
Strip or dip kit	$7.49 for two tests	Hardness, a quick look	Color steps, no certification, and the accuracy problems above
Single-parameter home kit	Varies by test; no reliable range found	One known concern, such as iron	Still unregulated. Bacteria kits usually need about 48 hours of waiting, per SFPUC guidance
Mail-in lab kit	$209 to $399 at Tap Score; $220 to $255 at WaterCheck, return shipping extra	A broad one-time panel, and homes far from a lab	Bacteria timing in the mail, and state certification may not apply. See choosing a lab
Local certified lab or health department	$21 to $55 in Washington for nitrate and coliform tests; $75 for Oklahoma’s annual well list of bacteria, nitrate and nitrite, pH and conductivity; free in nearly all Iowa counties for bacteria, nitrate, arsenic and manganese, for qualifying private wells	Yearly tests and anything that matters	You collect on the lab’s schedule and may need to drop off in person

Mail-in prices are seller list prices seen on 2 November 2026. Look for a university or county program too. Virginia’s household water clinics cost $70 a kit for a panel including bacteria, lead, arsenic and nitrate. The program’s own slides call the lab a research lab, not state-certified, with results for information and education, so it may not suit a sale. Wisconsin’s WellTAP may cover testing for some households with a pregnant person, a young child or someone with a weakened immune system.

What to test for

Start with the core four from EPA and CDC: total coliform bacteria, nitrate, TDS and pH. Ask for E. coli with the coliform test. Penn State pairs them, because E. coli points to animal waste or human sewage.

Then add arsenic and lead at least once. A clean core-four result says nothing about metals. Add the rest from what is around your well. This list follows EPA’s chart:

What you see or live near	Test for
Lead or copper plumbing, corroding pipes	pH, lead, copper, corrosion
Intensive farming	Nitrate, nitrite, pesticides, coliform
Mining	Metals, pH, corrosion
Gas drilling	Chloride, sodium, barium, strontium
Dump, factory, gas station or dry cleaner	VOCs, TDS, pH, sulfate, chloride, metals
Fuel smell or buried fuel tanks	VOCs
Salty taste or a salted road nearby	Chloride, TDS, sodium
Rust or black stains on fixtures or laundry	Iron, copper, manganese
Scale, or soap that will not lather	Hardness
Bad taste or smell	Hydrogen sulfide, corrosion, metals. Rotten egg smell has its own guide
Radon in your area or indoor air	Radon

Your county matters too. CDC says to ask your health or environmental department which local contaminants to add. Wisconsin, for example, names strontium for eastern and northern parts of the state and yearly arsenic in three counties. For radon, the state lab there notes that water tests are generally not necessary unless air radon levels are high. On PFAS, Wisconsin says testing is mainly for homes near a known contamination site. Our PFAS testing guide covers that decision. It costs far more: New Jersey estimates $600 to $900 per sample for the PFAS group that includes PFOA, PFOS and PFNA.

How often to test

Agencies agree on yearly bacteria testing and differ on the rest.

Source	Bacteria	Nitrate	pH, TDS	Metals
EPA	Yearly	Yearly	Yearly	Based on local risk
CDC	Yearly	Yearly	Yearly	Ask your health department
Minnesota	Yearly	Yearly in its nitrate guidance; its testing page says every other year	Not listed	Arsenic, lead and manganese at least once
Penn State	Yearly	Every 3 years if near septic or farms	Every 3 years	By land use, every 3 years
Iowa DNR	Yearly	Yearly	Not listed	Arsenic and manganese every 3 years
Wisconsin DHS	Yearly	Yearly	Not listed	Arsenic and lead every 5 years

A sensible default: bacteria and nitrate every year, a metals panel now and every 3 to 5 years, and pH and TDS whenever the lab offers them cheaply. If a past test found something, follow your health department, which may ask for more.

Test right away if

EPA and CDC name these triggers:

• Flooding, construction or land disturbance near the well
• Well repair, or replacement of any part of the system
• A change in taste, color or smell
• Known water problems in your area
• Someone becomes pregnant or a child comes to live with you

What testing costs: a worked example

These prices come from the Wisconsin State Laboratory of Hygiene list effective 1 July 2026. Other states and private labs will differ, so get a local quote.

Plan	Tests added	Running total	Usual lab time
Yearly minimum	Bacteria $35, nitrate $35	$70	2 to 3 business days
First wider check	Metals screen $97	$167	10 business days
Near fuel, a dump or a dry cleaner	VOC screen $141	$308	21 business days
High indoor radon	Radon in water $111	$419	5 business days for radon

The lab’s $450 Homeowner Package is the first three rows plus fluoride, atrazine and nitrite. By our arithmetic that is the exact sum of the separate prices, so there is no bundle saving. Buy only what your location calls for.

Over five years at those prices, $70 a year plus one metals screen comes to $447. One $209 mail-in panel followed by four yearly $70 tests comes to $489, before any shipping. Buying that $209 kit every year would cost $1,045. The useful pattern is one broad panel, then cheap yearly bacteria and nitrate tests.

How to choose a lab

1. Start with your state’s list. EPA keeps links to each state certification program. Your county health department will often know the closest lab, and some offer free well testing.
2. Ask whether the lab is certified in your state for those tests in drinking water. Certification is by state and by test. WaterCheck’s lab says it is certified in 38 states and territories and invites you to check yours. It calls one of its well kits an “informational” analysis.
3. Do not confuse ISO with state certification. Tap Score says its labs hold ISO/IEC 17025 and adds that this “does not mean every test is separately certified or approved by a regulatory agency”. An informational result can be useful, but it may not satisfy a state or a lender.
4. Read “EPA” claims carefully. EPA-approved methods exist for labs. That does not make a kit EPA-approved, and in the federal setup it is states that certify labs.
5. Ask about bacteria timing. See the sample steps below. Tap Score’s $399 kit includes overnight shipping and a cooler, and the seller aims it at wells with suspected bacteria. Its $209 kit lists coliform with standard two-day shipping to the lab, and offers overnight as a checkout choice, so ask which one keeps your sample within the lab’s limit. WaterCheck’s kits require next-day return shipping at your cost.
6. Ask for the reporting limit. It should sit below the benchmark you care about. A result of “less than” a number above the benchmark tells you nothing.
7. Check who gains from the result. Prefer a lab that does not sell treatment. If a dealer offers a free test, ask whether it covers coliform and nitrate and who ran it.

How to take a good sample

Bad sampling ruins good lab work. Your lab’s sheet overrides everything here, because methods differ. Virginia’s program says leave the aerator on, while Penn State says many labs recommend removing it for bacteria.

1. Plan the day. Call first. Penn State says most labs will not accept samples on Fridays or before holidays, and UW-Stevens Point takes no bacteria samples on Fridays. EPA Region 8 tells public systems to sample early in the week.
2. Know your clock. Penn State says to deliver bacteria samples within 24 hours. Oregon gives the same window for home sales. Public water systems work to 30 hours, and EPA Region 8 warns the sample must arrive before that, so the lab has time to start.
3. Use the lab’s bottles. Some contain a chemical that removes chlorine, so do not rinse them unless told to. Never reuse a food or drink container.
4. Pick the right tap. Drinking water usually comes from the cold kitchen tap. To test the well itself, Penn State says to use the spigot at the pressure tank, before any softener or filter. Test after treatment too if you want to know the system works.
5. Take lead and copper first. These need water that has stood in the pipes: 6 to 8 hours in Virginia’s instructions, at least 12 in Penn State’s. Collect before anyone uses water in the morning.
6. Then flush and take the rest. Virginia runs the tap at least a minute. Penn State says a few minutes. Do not touch the inside of the cap or bottle.
7. Keep it cold and move fast. Refrigerate or use ice, and get it to the lab the same day if you can.

Wait after chlorinating. If you have shock chlorinated the well, give the chlorine time to clear before a bacteria test. Timing advice varies: CDC says at least 7 to 10 days, Minnesota 2 to 4 weeks, and Penn State 10 to 14 days. Ask your lab or health department.

How to read your results

Penn State’s guide explains the report. Most results are in mg/L, which is the same as ppm. Bacteria appear per 100 mL, often as MPN, “most probable number”. Labs do not report zero. “<0.003” means nothing was found above the lab’s limit. “>201” means more bacteria than the lab could count.

Watch the nitrate unit. EPA’s benchmark is 10 mg/L as nitrogen. By molecular weight that is about 44 mg/L as nitrate (our calculation). A report showing “30 mg/L” could be either, so check the label.

The figures below are written for public water systems, not for private wells. Use them as benchmarks. Being under one does not prove water is safe. Several have a health goal of zero.

Test	Benchmark	Note
Total coliform, E. coli	None detected	Health-based standard is zero. Treat any positive as a problem
Nitrate	10 mg/L as N	Nitrite is 1 mg/L as N. 40 CFR 141.62
Arsenic	0.010 mg/L (10 µg/L)	Health goal is zero. 40 CFR 141.62
Lead	Action level 0.015 mg/L today; 0.010 mg/L applies from 1 November 2027	An action level is not a safe level. EPA sets the goal at zero
Copper	Action level 1.3 mg/L	Health goal is also 1.3 mg/L
Fluoride	4.0 mg/L; 2.0 mg/L secondary	40 CFR 141.62 and 143.3
Uranium	30 µg/L	40 CFR 141.66. Health goal is zero
Manganese	0.05 mg/L secondary	Minnesota’s health guidance is 100 µg/L or less for infants who drink tap water or formula made with it, and 300 µg/L or less for others
Iron	0.3 mg/L secondary	Staining and taste. Not federally enforced
pH	6.5 to 8.5 secondary	Low pH can point to corrosion
TDS	500 mg/L secondary	Penn State also watches for change between tests
Chloride, sulfate	250 mg/L each, secondary	Chloride can point to road salt or drilling
Hardness	No federal limit	Connecticut DPH: no recognized standard
PFOA, PFOS	4.0 ppt each	40 CFR 141.61. Systems must comply by 26 April 2029. Proposed changes were not final as of 2 November 2026

If a result comes back high

Take results to your county or state health department first, not to a product. CDC says the same: switch to a safe source, then ask them to help interpret results and plan next steps.

Coliform or E. coli

Minnesota’s advice for coliform: use boiled or bottled water for drinking and cooking. If nitrate or arsenic was also found, do not rely on boiling, because it can concentrate them. Disinfect the well or hire a licensed contractor, then retest. If bacteria return, work with a contractor, since the cause may be debris, a cracked casing or surface water getting in. Boiling is a stopgap, not a fix. Penn State treats E. coli as more serious than coliform alone, because it means human or animal waste is entering the water.

Nitrate above 10 mg/L as N

Minnesota’s advice: switch to a safe source such as bottled water. Do not give the water to babies under six months. Bottle-fed babies that age are at the highest risk of blue baby syndrome. Even with home treatment, Minnesota says these babies should not drink it, in case treatment fails. Do not boil it: boiling raises the nitrate level. Have a licensed contractor inspect the well and look for sources on your property.

Lead

CDC says boiling will not reduce lead, and that no safe blood lead level has been identified for young children. Compare first-draw and flushed samples. In the Virginia study, a 5-minute flush brought most systems under 15 µg/L, but some went up, perhaps from particles or lead-bearing parts upstream of the faucet. Do not assume flushing works in your house.

Fuel or chemical smell

Stop using the water and call your health department. CDC is plain on this: boiling and disinfection will not make it safe.

Once you know what is in the water, our well water filtration guide covers treatment order. A softener is not a safety device, and no filter should go on before you know what it needs to remove.

Buying or selling a home

Rules vary by state. Two examples:

• Oregon: the seller must test for arsenic, nitrate and total coliform at an accredited lab, and send results to the buyer and the state within 90 days.
• New Jersey: the Private Well Testing Act requires testing before closing, at a state-certified lab. It does not stop a sale if the water is over a standard, so buyer and seller negotiate what happens next.

Elsewhere, write a test into the offer. Have the lab or an independent person collect the sample, and ask your lender what it needs. Wisconsin’s state lab sells a $146 HUD/FHA-VA loan package covering coliform, E. coli, lead, nitrate and nitrite, which shows the sort of panel lenders can ask for. Add arsenic and anything local. A loan panel is a minimum, not a full picture.

This page is general information, not medical or professional advice. For test results or illness, contact your state or county health department or a certified lab. Lab prices and seller listings change, so check them before you order.

Facts checked against primary sources on 2 November 2026.