Certified well water labs in Connecticut (2026)

WellTestList · Wednesday, October 7, 2026 · state page

Connecticut has about 342,000 private residential wells serving roughly 23% of the state (more than 837,000 people), according to the Department of Public Health. DPH’s advice is simple: use any state-approved lab, and DPH’s July 2026 list shows 14 in-state labs that take private-well samples. A few town health departments run their own certified labs. Stamford’s charges $40 for bacteria and $80 for a full one-sample test. For a new well, testing is required by law before anyone uses the water. Since October 2022 that test has to include arsenic and uranium.

The short version

1. Existing well? Test the “basic indicators” every year, and arsenic, uranium, and radon at least once. That’s DPH’s schedule: bacteria plus a standard chemistry panel yearly; lead (first-draw and flushed) at least once; arsenic, uranium, and radon at least once, ideally every five years; VOCs at least once; fluoride every five years if a child under 12 lives there. Use any lab on the DPH approved-lab list that is marked for private wells.
2. Just drilled a new well? Test before you drink it. State law (CGS §19a-37) requires the owner to test a new private well for the basic indicators plus arsenic and uranium, and first-draw lead if the well serves an existing house. Your local health department has to approve the results before the water is used.
3. Selling, buying, or renting out? No sale test is required by state law; lender tests are a bank requirement. But the seller or landlord must tell the buyer or tenant that DPH’s private well testing guidance exists. If a test shows a contaminant over the limit, landlords have 48 hours to pass the result on to tenants.

How Connecticut’s system actually works

Private household wells aren’t regulated by EPA, and in Connecticut the owner is responsible for testing and upkeep. Local health departments and districts approve where a new well goes before it’s drilled. After that, the rules that matter are in CGS §19a-37 and the Public Health Code’s §19-13-B101:

• New wells (on and after October 1, 2022): coliform, nitrate, nitrite, sodium, chloride, iron, manganese, hardness, turbidity, pH, sulfate, apparent color, odor, arsenic and uranium, tested by a state-approved lab. The well has to be disinfected first, and sampling waits until the chlorine is gone. Results go to your local health department, and the water isn’t used for domestic purposes until it approves them. The local director of health can also require radium, radon, or gross alpha where the bedrock is known to carry them, and pesticides or VOCs if nitrate is over 10 mg/L or the well is near a known chemical site.
• Who can collect: lab staff, certified water operators, and health-department staff. A homeowner or a new-construction general contractor can also collect, as long as the lab provides the instructions.
• Labs report private-well results to the local health department and to DPH within 30 days. Those results are confidential, with narrow exceptions (for example, a buyer who has signed a purchase contract). DPH is building an online reporting portal for labs this year.
• Home sales: state law doesn’t require a test when you sell. If an existing well is sampled within six months of a sale, a qualified person has to collect the sample and a state-approved lab has to run it.

DPH’s full recommended list is in its Private Well Testing guidance (updated May 2026). The yearly “basic indicators” panel is total coliform, nitrate (limit 10 mg/L), nitrite (1 mg/L), sodium (100 mg/L), chloride (250 mg/L), iron, manganese (0.3 mg/L health-based), hardness, pH (6.5–8.5), turbidity, sulfate, apparent color, and odor. Retest after any work on the well, pump, or pipes, or if the wellhead floods. Questions: DPH Private Well Program, 860-509-8401.

Options we verified

What we could confirm with a public URL tonight: DPH’s drinking-water lab list dated July 2, 2026, the Stamford and Greenwich health-department lab pages, Aquatek’s FAQ, UConn Extension’s program pages, and the mail-in product pages:

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What Connecticut water tends to have

• Arsenic, uranium, radon — DPH says all three occur naturally in groundwater in some parts of the state. High levels have turned up “sporadically” around Connecticut and can fluctuate, which is why DPH says to test at least once and ideally every five years. Arsenic and uranium are now part of the required new-well test. If uranium in water is over 30 µg/L, or radon in your indoor air is over 4 pCi/L, DPH suggests testing for uranium, radium, and radon together.
• Radon in water — DPH’s recommended action level is 5,000 pCi/L, based on the average of two samples taken at the same time from the same spot (fact sheet, revised Feb 2025). Below 10,000 pCi/L a carbon (GAC) system can work; above that, aeration. Test the air in your house too.
• Lead and copper — usually from plumbing, especially when water is corrosive (low pH). Collect a first-draw sample (water that sat at least six hours) and a flushed one.
• Nitrate, sodium, chloride, bacteria — from septic systems, fertilizer, and road salt. If your well is within a quarter mile of a current or former orchard or farm, DPH suggests adding arsenic and pesticides. Near commercial or industrial land, add VOCs. If the house foundation was treated for termites before 1990, ask about dieldrin and chlordane.
• PFAS — Connecticut has private-well action levels of 0.016 µg/L (16 ppt) for PFOA, 0.01 µg/L (10 ppt) for PFOS, 0.012 µg/L for PFNA, and 0.049 µg/L for PFHxS. It isn’t in any routine panel. Check the free DPH/UConn program first. See our PFAS Method 533 / 537.1 guide.

Mail-in kits (for a broader PDF)

These are independent labs that mail bottles, test, and email a PDF, and they don’t pitch you a softener while they’re at it. In Connecticut they make the most sense when you want a wide list of analytes in one report and no new-well or sale paperwork is involved. For those, use a lab on DPH’s list and follow its collection rules. National Testing Laboratories (Ypsilanti, MI) appears on DPH’s July 2026 list of approved out-of-state labs (PH-0745). Listed prices we checked for this ship (same national SKUs as other state pages):

• Tap Score / SimpleLab Essential Well: $209 listed (54 analytes; standard shipping and prepaid return on the product page).
• National Testing Laboratories WaterCheck Basic: $220 listed plus free delivery on watercheck.com. Next-day return shipping is not included. Budget for overnight return on the bacteria bottle.

Those are listed prices, not coupons. A new-well test in Connecticut has to come from a state-approved lab and cover every analyte in §19a-37, so check before you rely on a mail-in kit for that.

Side by side for a Connecticut well

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Real estate, lenders, and landlords

Connecticut does not require a water test when you sell. DPH stresses that the tests banks ask for at closing are a lender requirement, not the law, and don’t necessarily cover everything. What the law does require (CGS §19a-37(d)) is that before a sale, exchange, or rental of a property with a private well, the owner tells the buyer or tenant that DPH’s educational material on well testing is available. The buyer’s real estate agent, or else the owner, landlord, or closing attorney, hands over a copy. Leaving it out doesn’t void the sale. That handout recommends the same yearly basic indicators, lead at least once, arsenic / uranium / radon at least once, VOCs at least once, and fluoride every five years with kids under 12. If a well is tested within six months of a sale, a qualified person has to collect the sample and an approved lab has to run it. The results go to the town health department within 30 days.

Landlords: under CGS §19a-37k, when any test of a rental property’s water exceeds a state maximum contaminant level or a DPH action level, the owner must forward the result to every tenant within 48 hours. The local director of health checks that it happened. More: home purchase / lender chain of custody.

Related: New York · Vermont · New Hampshire · New Jersey · Maine · PFAS 533 / 537.1 · how to read a report · after a flood · lender / CoC · cost table · Home Depot free kit vs a certified lab · How it works · back to the directory.