Certified Lab Directory
Certified Water Testing Labs in Connecticut
Not every lab that will take your money is approved to test drinking water. In Connecticut, that approval comes from the Connecticut Department of Public Health (DPH) — and it requires EPA-approved methods, annual proficiency tests, and on-site audits. Below are the 17 labs based in Connecticut that currently hold it. If you're testing a private well, the EPA recommends doing this once a year, so it's worth finding one you like.
Certified drinking water labs in Connecticut
DPH's list carries a column headed "Private Well Testing," which the PDF defines as "laboratories that accept samples from private wells." 3 of the 17 laboratories below are not marked in it; 14 are. As DPH puts it: "All commercial labs on this list are approved to test drinking water; however only some of these labs offer testing services for private wells."
| Lab | City | Phone | Private Well Testing |
|---|---|---|---|
| Microbac Laboratories, INC. - Dayville | Dayville | 860-774-6814 | Yes |
| Greenwich Health Department Laboratory | Greenwich | 203-622-7843 | Yes |
| Environmental Consulting Lab | Madison | 203-245-0568 | Yes |
| Phoenix Environmental Laboratories, Inc. | Manchester | 860-645-1102 | No |
| EMSL Analytical, Inc. - CT | Meriden | 203-284-5948 | Yes |
| Regional Water Authority | New Haven | 203-401-2700 | Yes |
| ALS Environmental - Newtown | Newtown | 203-270-9973 | Yes |
| Northwest Environmental Water Labs | Oakville | 203-437-4110 | Yes |
| Eastern Analytical Laboratory, Inc. | Old Saybrook | 860-388-2378 | Yes |
| Northeast Laboratories, Inc | Rocky Hill | 860-828-9787 | Yes |
| Stamford Health Department Laboratory | Stamford | 203-977-4378 | Yes |
| ALS Environmental - Stratford | Stratford | 203-325-1371 | No |
| Complete Environmental Testing, Inc. | Stratford | 203-377-9984 | No |
| Environmental Monitoring Lab | Wallingford | 203-284-0555 | Yes |
| South Norwalk Electric & Water Laboratory | Wilton | 203-762-7884 | Yes |
| Envirotech Laboratory | Windsor | 860-688-7249 | Yes |
| Aquatek Labs, Inc. | Woodbridge | 203-389-1824 | Yes |
Certification status changes — labs are added, dropped, and suspended throughout the year. Before you mail a sample, confirm the lab still holds certification for the specific test you need. This list was pulled from the official source on .
Source: Connecticut Department of Public Health (DPH), Environmental Laboratory Certification Program (PDF). List dated July 2, 2026; retrieved . (https://portal.ct.gov/dph/-/media/dph/dph-2025/environmental-lab-certification/lab-lists/in-state-laboratories-certified-to-test-drinking-water_072026.pdf)
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Get the Free Test KitHow lab certification works in Connecticut
In Connecticut, drinking water laboratories are certified by the Connecticut Department of Public Health (DPH) under the Environmental Laboratory Certification Program. The program operates within the EPA's national framework for drinking water lab certification: labs must use EPA-approved analytical methods, successfully analyze proficiency-test samples at least annually for each certified method and analyte, and pass periodic on-site audits (EPA, epa.gov/dwlabcert). Certification is issued per method and per analyte — so a lab certified for bacteria testing isn't automatically certified for metals or radiochemistry. When you call, name the specific test you need.
Connecticut's list is in-state only, and it is complete: these 17 are every approved commercial laboratory located in the state. DPH does not publish its out-of-state approvals at all — the PDF says to request those from the Approval Program directly. Not every lab on that list takes private-well samples, which is why the table above reproduces the PDF's "Private Well Testing" column.
Questions about a lab's certification status go to the program directly: 860-509-7389.
Common questions about Connecticut water testing labs
Who certifies water testing labs in Connecticut?
The Connecticut Department of Public Health (DPH), through the Environmental Laboratory Certification Program. The program follows the EPA's national framework for drinking water laboratory certification, which requires EPA-approved test methods, at least annual proficiency testing, and periodic on-site audits. Source: Connecticut Department of Public Health (DPH), Environmental Laboratory Certification Program (https://portal.ct.gov/dph/-/media/dph/dph-2025/environmental-lab-certification/lab-lists/in-state-laboratories-certified-to-test-drinking-water_072026.pdf) and EPA (epa.gov/dwlabcert).
How many certified labs are in Connecticut?
17 certified drinking water labs are located in Connecticut, as of the official list we pulled on August 7, 2026. Certification changes throughout the year, so treat this as a starting point and confirm status with the lab. Source: Connecticut Department of Public Health (DPH), Environmental Laboratory Certification Program (https://portal.ct.gov/dph/-/media/dph/dph-2025/environmental-lab-certification/lab-lists/in-state-laboratories-certified-to-test-drinking-water_072026.pdf).
How often should I test my well water in Connecticut?
The EPA recommends testing private wells annually for total coliform bacteria, nitrates, total dissolved solids, and pH — and testing immediately after flooding, well repairs, nearby construction, or any change in your water's taste, odor, or color. Your local health department can tell you which contaminants are common in Connecticut groundwater. Source: EPA, Protect Your Home's Water (epa.gov/privatewells).
Can I use a lab that isn't on this list?
This list covers labs located in Connecticut that were on the official list published by the Connecticut Department of Public Health (DPH) as of August 7, 2026. Certification changes during the year, so a lab missing from this page may have been certified since then — the official source linked above always has the current list. What we'd avoid is any lab that can't show a current drinking water certification at all. The EPA's guidance is to only use certified laboratories for drinking water testing. Source: EPA, Protect Your Home's Water (epa.gov/privatewells).
What if the nearest certified lab is far from me?
Ask the lab about a mail-in collection kit — many certified labs ship one with instructions and pre-treated bottles. Timing matters for some tests (bacteria samples have a short window between collection and analysis), so follow the lab's collection instructions exactly. Your local health department is also worth a call; some offer private well testing for free. Source on health department testing: EPA, Protect Your Home's Water (epa.gov/privatewells).
Lab results came back with a problem?
High hardness, high TDS, or a contaminant above EPA limits can usually be treated at the house. Send us what the lab found and we'll build a filtration estimate around your report.
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