Arsenic Water Testing Labs in Connecticut (16 state-certified labs)
Labs on Connecticut's official certification list that test drinking water for arsenic, with the ones that take homeowner samples first.
11 named for arsenic itself on the list.
Per the state list or a state web page. Call to confirm.
Located outside Connecticut but on its list.
USGS estimate for Connecticut.
How many labs test for arsenic in Connecticut
16 labs on Connecticut's official drinking-water lab list are certified to test for arsenic. Of these, 11 are named for arsenic itself and 5 hold a group certification that includes it. 12 of them are marked as taking samples from the public. They are listed first.
The list is published by the Connecticut Department of Public Health - Environmental Laboratory Certification Program. List version on file: 10/09/2026. Fetched 2026-10-29 (UTC).
Connecticut labs certified for arsenic
Marked as taking public samples (12)
| Lab | Location | Arsenic certification | Public samples | Cert. expiry |
|---|---|---|---|---|
| ALS Environmental - Newtown | Newtown, CT | Named on the official list | Public samples: yes (per state) | Not on the list |
| Aquatek Labs, Inc. | Woodbridge, CT | Named on the official list | Public samples: yes (per state) | Not on the list |
| Eastern Analytical Laboratory, Inc. | Old Saybrook, CT | Certified for a group that includes arsenic: confirm with the lab | Public samples: yes (per state) | Not on the list |
| Environmental Consulting Lab | Madison, CT | Named on the official list | Public samples: yes (per state) | Not on the list |
| Environmental Monitoring Lab | Wallingford, CT | Named on the official list | Public samples: yes (per state) | Not on the list |
| Envirotech Laboratory | Windsor, CT | Certified for a group that includes arsenic: confirm with the lab | Public samples: yes (per state) | Not on the list |
| Greenwich Health Department Laboratory | Greenwich, CT | Named on the official list | Public samples: yes (per state) | Not on the list |
| Microbac Laboratories, INC. - Dayville | Dayville, CT | Named on the official list | Public samples: yes (per state) | Not on the list |
| Northeast Laboratories, Inc | Rocky Hill, CT | Certified for a group that includes arsenic: confirm with the lab | Public samples: yes (per state) | Not on the list |
| Northwest Environmental Water Labs | Waterbury, CT | Named on the official list | Public samples: yes (per state) | Not on the list |
| Regional Water Authority | New Haven, CT | Named on the official list | Public samples: yes (per state) | Not on the list |
| Stamford Health Department Laboratory | Stamford, CT | Certified for a group that includes arsenic: confirm with the lab | Public samples: yes (per state) | Not on the list |
Other labs on the list (4)
| Lab | Location | Arsenic certification | Public samples | Cert. expiry |
|---|---|---|---|---|
| ALS Environmental - Stratford | Stratford, CT | Named on the official list | Not marked as taking public samples | Not on the list |
| Complete Environmental Testing, Inc. | Stratford, CT | Named on the official list | Not marked as taking public samples | Not on the list |
| Phoenix Environmental Laboratories, Inc. | Manchester, CT | Named on the official list | Not marked as taking public samples | Not on the list |
| South Norwalk Electric & Water Laboratory | Wilton, CT | Certified for a group that includes arsenic: confirm with the lab | Not marked as taking public samples | Not on the list |
How the Connecticut list marks public samples (whole list). Explicit 'Private Well Testing' column.
Before you send a sample, call the lab to confirm it is currently certified for the exact test and method, that it accepts samples from homeowners, and how to collect and ship them. Status can change between list updates.
Why test for arsenic in Connecticut
Arsenic is invisible, tasteless and mostly natural, and it comes in two forms that respond very differently to treatment. Read our arsenic explainer.
Connecticut guidance that mentions arsenic:
- Connecticut's health department guidance, as summarized by the state legislature's research office in 2019: basic indicators every year; lead at least once; arsenic, uranium and radon at least once and ideally every five years; VOCs at least once. [1]
- New wells: since October 1, 2022, the owner of every newly built private well must have it tested by a laboratory, including coliform, nitrate, nitrite, sodium, chloride, iron, manganese, hardness, turbidity, pH, sulfate, color, odor, arsenic and uranium (plus a first-draw lead sample if the well serves an existing building), and send the results to the local health authority. A new well may not be used for household purposes until the local health authority finds the results meet the state limits. [2]
- The local director of health may require testing for arsenic, radium, uranium, radon or gross alpha where there are reasonable grounds to suspect them, such as known local geology. [2]
USGS estimates that the most private-well users with arsenic above 10 µg/L, EPA's limit for public water, live in Tolland County, Fairfield County and New Haven County (about 12,109 people in Tolland County, 2010 base year). USGS describes this kind of estimate as useful "for broad screening of the population at risk", so it says nothing certain about any one well. [3]
Show the numbers
| Item | Value | Note |
|---|---|---|
| Tolland County | 12,109 people (2010 base year) | |
| Fairfield County | 11,418 people (2010 base year) | |
| New Haven County | 6,752 people (2010 base year) | |
| Middlesex County | 6,056 people (2010 base year) | |
| Windham County | 5,826 people (2010 base year) | |
| Hartford County | 3,591 people (2010 base year) |
USGS model estimate for broad screening, not a measurement of any well. Only a test tells you about your own well. Source: USGS, Estimated county level domestic well population with arsenic greater than 10 micrograms per liter (Ayotte, Medalie and Qi, 2017), accessed 2026-11-01.
About 861,472 people in Connecticut used private wells in 2015, by the USGS estimate of people on domestic self-supplied water. [4] Federal limits are written for public water systems, not private wells, so testing is up to the owner.
For tests that depend on your home (farms nearby, old plumbing, a new baby), use the which-tests checklist. When results arrive, check your numbers against EPA's limits. State guidance, county data and every lab: Connecticut.
Other tests in Connecticut
- Connecticut General Assembly OLR Research Report 2019-R-0246, Private well testing (Oct 16, 2019)
- Connecticut General Statutes § 19a-37 (current, chapter 368a)
- USGS, Estimated county level domestic well population with arsenic greater than 10 micrograms per liter (Ayotte, Medalie and Qi, 2017)
- USGS, Estimated use of water in the United States, county-level data for 2015 (Dieter et al., ver. 2.0, 2018)
- CT DPH In-State Approved Commercial Laboratories Certified to Test Drinking Water (official list)
CT DPH In-State Approved Commercial Laboratories Certified to Test Drinking Water.
Official source