Certified labs by state
Connecticut
About 23% of Connecticut residents rely on private residential wells, and the Connecticut Department of Public Health (DPH) is the main state agency residents use for private-well guidance. Connecticut also maintains a resident-facing Test Your Well portal that points homeowners to state-approved drinking-water labs and testing guidance. ([portal.ct.gov](https://portal.ct.gov/dph/Environmental-Health/Private-Well-Water-Program/Private-Wells?utm_source=openai))
Checked against official sources on October 4, 2026. Rules and links change; confirm with the office listed before you act.
- Certifies drinking water labs
- Connecticut Department of Public Health, Environmental Laboratory Certification Program (ELCP) ([portal.ct.gov](https://portal.ct.gov/dph/environmental-health/environmental-laboratory-certification/environmental-laboratory-certification))
- Official certified lab list
- Official page →
- Free or low-cost testing
- UConn Extension says its rural low-cost well-testing effort had grant funds that offset most costs, but those funds are exhausted while it seeks more grants; no statewide free private-well testing program was found on the official sources reviewed. ([ctiwr.uconn.edu](https://ctiwr.uconn.edu/well-testing/))
Official resources in Connecticut
State landing page for private-well owners, linking to testing guidance, fact sheets, local health departments, and treatment resources. ([portal.ct.gov](https://portal.ct.gov/dph/environmental-health/private-well-water-program?utm_source=openai))
Current DPH page showing which contaminants to test for, how often to test, and when extra testing is warranted. ([portal.ct.gov](https://portal.ct.gov/dph/knowledge-base/articles/environmental-health/drinking-water/educational-materials))
Official DPH certification page with current approved-laboratory lists, including labs certified to test drinking water. ([portal.ct.gov](https://portal.ct.gov/dph/environmental-health/environmental-laboratory-certification/environmental-laboratory-certification))
UConn page describing low-cost well-testing workshops in rural Connecticut and the current grant-funding status. ([ctiwr.uconn.edu](https://ctiwr.uconn.edu/well-testing/))
Key facts for Connecticut
- Connecticut reports about 342,356 private residential wells serving roughly 23% of residents, or more than 837,000 people. ([portal.ct.gov](https://portal.ct.gov/dph/Environmental-Health/Private-Well-Water-Program/Private-Wells?utm_source=openai))
- DPH recommends testing basic indicators every year, and again after repairs to the well, pump, or water pipes, or after flooding. ([portal.ct.gov](https://portal.ct.gov/dph/knowledge-base/articles/environmental-health/drinking-water/educational-materials))
- DPH recommends lead testing at least once; if water is corrosive, retest every 3-5 years. ([portal.ct.gov](https://portal.ct.gov/-/media/Departments-and-Agencies/DPH/dph/environmental_health/private_wells/Publications/24aPrivateWellTestingShortVersion51419.pdf))
- DPH recommends testing arsenic, uranium, and radon at least once, ideally every 5 years, because elevated levels occur in some Connecticut wells. ([portal.ct.gov](https://portal.ct.gov/-/media/Departments-and-Agencies/DPH/dph/environmental_health/private_wells/Publications/24aPrivateWellTestingShortVersion51419.pdf))
- Nitrate is part of Connecticut's basic indicators panel, and DPH lists the drinking-water standard as 10 mg/L. ([portal.ct.gov](https://portal.ct.gov/-/media/Departments-and-Agencies/DPH/dph/environmental_health/private_wells/Publications/24aPrivateWellTestingShortVersion51419.pdf))
- DPH recommends VOC testing at least once, and more often if gasoline, oil, solvents, or industrial chemicals are suspected nearby. ([portal.ct.gov](https://portal.ct.gov/-/media/Departments-and-Agencies/DPH/dph/environmental_health/private_wells/Publications/24aPrivateWellTestingShortVersion51419.pdf))
What to do next
- Use a Connecticut-approved lab and confirm it is certified for the specific analytes you need, especially radiologicals such as uranium or radon. ([portal.ct.gov](https://portal.ct.gov/dph/knowledge-base/articles/environmental-health/drinking-water/educational-materials))
- Ask your local health department whether your town has area-specific problems, and ask neighbors about known water-quality issues before deciding on extra tests. ([portal.ct.gov](https://portal.ct.gov/dph/knowledge-base/articles/environmental-health/drinking-water/educational-materials))
- Keep dated test records and retest promptly if water taste, color, odor, or clarity changes. ([portal.ct.gov](https://portal.ct.gov/dph/knowledge-base/articles/environmental-health/drinking-water/educational-materials))
Helpful guides
- How to choose a state-certified drinking water lab
- What to test your private well water for (and how often)
- How to collect a well water sample without ruining the test
- How to read a water test report: MCLs, units and flags