Is New Haven, CT Tap Water Safe to Drink?

Where Does New Haven Get Its Water?

New Haven's drinking water is supplied by the Regional Water Authority, a regional utility serving the greater New Haven area. The system draws from a combination of surface water reservoirs and groundwater wells across the region.

The authority operates several treatment plants, including the Lake Gaillard Treatment Plant, Lake Saltonstall Water Treatment Plant, Lake Whitney Treatment Plant, and the West River Water Treatment Plant. Groundwater is also drawn from well fields including the North and South Sleeping Giant Wellfields, North and South Cheshire Wellfields, and individual wells such as Derby Well and the Seymour Well.

Together these sources and facilities give the system multiple points of supply, which provides some redundancy. Most residents receive water drawn from the reservoir system, though groundwater sources supplement supply as needed.

How Is New Haven Tap Water Treated?

The Regional Water Authority uses a multi-step treatment process. Surface water from the reservoirs goes through coagulation, dissolved air flotation, and filtration before reaching your tap. Groundwater sources also receive treatment before distribution.

Disinfection uses a combination of ozone and free chlorine, and some portions of the system use chloramines. Ozone is applied early in the treatment train to neutralize pathogens and reduce organic compounds; a chlorine-based residual is then maintained through the distribution system to keep the water safe as it travels to your home.

The system also uses adsorption and aeration steps at various facilities, which help reduce taste and odor compounds and certain dissolved gases from the groundwater sources.

What's in New Haven Tap Water?

The most significant finding in recent EPA testing is PFOS, one of the most studied PFAS compounds. The highest detected level in the New Haven system was 0.0107 micrograms per liter, which is nearly three times EPA's new federal limit of 0.004 micrograms per liter. All 28 ZIP codes in this dataset showed detections above that limit.

Several other PFAS compounds were also detected, including PFTrDA, HFPO-DA, and PFBA. Their measured values were at or near the laboratory reporting threshold, and none exceeded a regulatory limit in the current data. Lithium was also detected at up to 9 micrograms per liter, which is at the reporting threshold and does not exceed any guideline in the data.

PFAS compounds like PFOS originate from industrial and commercial uses, including firefighting foams, non-stick coatings, and stain-resistant products. They persist in the environment and can move into surface water and groundwater over time. The Regional Water Authority is aware of this class of contaminants and utilities nationally are in the process of evaluating treatment upgrades to meet the 2024 EPA standards.

Health Risk Profile for New Haven

PFOS was measured at 0.0107 micrograms per liter, above EPA's enforceable federal maximum of 0.004 micrograms per liter established in 2024. Utilities have until 2031 to achieve full compliance, so this is not a current violation of a compliance deadline, but the level is above the health-based standard EPA set to be protective over a lifetime of exposure.

Infants, pregnant individuals, and people who are immunocompromised face greater risk from PFOS exposure. EPA set the PFOS limit specifically with long-term health effects in mind, including impacts on immune function, thyroid health, and developmental outcomes in children. If you are in one of these groups, filtering your tap water is a reasonable precaution now.

A reverse osmosis filter certified to NSF/ANSI 58 and also certified to NSF/ANSI P473 (the specific PFAS standard) will remove PFOS and related compounds effectively. NSF/ANSI is an independent third-party certification label, so look for both marks on the filter packaging or the manufacturer's website before buying. A pitcher or faucet filter without those specific certifications may not reduce PFAS meaningfully.

The other PFAS compounds detected, PFTrDA, HFPO-DA, and PFBA, were found at or near the minimum detection level and do not exceed any current federal limit. The science on the health effects of these compounds continues to evolve, and EPA may set standards for some of them in future rulemakings.