- EPA's UCMR 5 testing looked for 30 contaminants here and found 4.
- PFOA (a PFAS): found in 11 of 12 samples, average 4.5 ppt, highest 5.6 ppt (EPA UCMR 5 testing, Oct 2024–Aug 2025) PFOA or PFOS averaged above 4.0 ppt in UCMR 5 testing
- PFHxA (a PFAS): found in 6 of 12 samples, average 1.7 ppt, highest 4 ppt (EPA UCMR 5 testing, Oct 2024–Aug 2025)
- PFOS (a PFAS): found in 2 of 12 samples, average 0.70 ppt, highest 4.1 ppt (EPA UCMR 5 testing, Oct 2024–Aug 2025)
- PFPeA (a PFAS): found in 2 of 12 samples, average 0.60 ppt, highest 3.8 ppt (EPA UCMR 5 testing, Oct 2024–Aug 2025)
- Lead, 90th percentile: 0 ppb at the latest result in EPA records for a monitoring period that ran on or after July 1, 2021, at or below EPA's 15 ppb action level (EPA SDWIS, monitoring period Jan 1, 2026–Dec 31, 2026). The 90th percentile is a system-wide measure from homes sampled under EPA's lead rule; it isn't a result for your home.
Public EPA test results
Can you drink Greenwich tap water? What EPA records show
EPA CT0570011 · serves Greenwich, CT · about 53,297 people (EPA SDWIS)
This report shows EPA's federal records for this water system: UCMR 5 testing, lead testing and violations. It isn't a test of the water at your tap, and it has no Water Score.
Public EPA test results
Aquarion-Greenwich (EPA CT0570011)
EPA data as of October 14, 2026. For Greenwich's main utility, Aquarion-Greenwich: We found no health-based violations in EPA's records for this system (CT0570011) since July 1, 2021, as of October 14, 2026. This water system averaged above 4.0 ppt for PFOA or PFOS in EPA's UCMR 5 testing. This is public data, not a test of your tap.
What EPA records show for Aquarion-Greenwich, as of October 14, 2026
We found no health-based violations in EPA's records for this system (CT0570011) since July 1, 2021, as of October 14, 2026.
Source: EPA ECHO record for Aquarion-Greenwich (SDWIS). Data as of October 14, 2026.
Lead, 90th percentile: 0 ppb at the latest result in EPA records for a monitoring period that ran on or after July 1, 2021, at or below EPA's 15 ppb action level (EPA SDWIS, monitoring period Jan 1, 2026–Dec 31, 2026). The 90th percentile is a system-wide measure from homes sampled under EPA's lead rule; it isn't a result for your home.
This water system averaged above 4.0 ppt for PFOA or PFOS in EPA's UCMR 5 testing.
EPA's UCMR 5 testing looked for 30 contaminants here and found 4.
Source: EPA records (SDWIS, UCMR 5). SDWIS: data as of Oct 14, 2026. EPA UCMR 5 data, samples through June 2026.
Your water bill names your utility.
Does Aquarion-Greenwich use chloramine?
We didn't find chloramine in Aquarion-Greenwich's EPA treatment records. That's not a complete list; your utility's annual water quality report says which disinfectant it uses.