Water

Rivers, Lakes, and Estuaries                Water of Long Island Sound               Warming and Rising Waters               Swimming               Clamming and Oystering       

Drinking Water

 

In 2024, 99.81 percent of the population served by community water systems (CWS) and 94.64 percent of all CWS demonstrated full compliance with applicable drinking water standards, based on an annual average. Data for 2024 indicates that the percentage of the population served by CWS that met drinking water standards was greater than the previous ten-year annual average of 98.5 percent. The percentage of CWS that met drinking water standards in 2024 was also greater than the previous ten-year annual average of 94.4 percent.⁴⁷ By far, the most common problem during 2024 in water systems was excessive levels of chloride.⁴⁸ Source water protection is important for ensuring the safety and quantity of drinking water supplies.

In June 2022, the Connecticut Department of Public Health (DPH) updated the “Drinking Water Action Level for Per And Polyfluoroalkyl Substances (PFAS) and renewed its recommendation to all public water systems (PWS) to test the water delivered to their customers for PFAS.⁴⁹ The Environmental Protection Agency (EPA)’s Fifth Unregulated Contaminant Monitoring Rule (UCMR 5) required PWS to sample for PFAS in their water supplies from 2024 to 2026. In 2024, 39 PWS (11 percent) completed their quarterly sampling requirements, with 19 having a “running annual average” of a PFAS above EPA’s Maximum Contaminant Level (MCL). The EPA anticipated that approximately one-third of all systems will collect samples each year between 2023 and 2025; however, EPA may reduce the number of small systems that will be asked to perform monitoring.⁵⁰

Over 80 percent of people in Connecticut are supplied by the public water systems, while the remainder of the population primarily relies on private wells, which are not monitored by any government agency and are not counted in this indicator. The DPH provides guidelines for testing of private wells.

Goal: The EPA’s current strategic plan identified a goal to reduce the number of community water systems nationwide that are still in noncompliance with health-based standards since March 31, 2021, from 752 to 500 by September 30, 2026; however, it is unclear how many of these non-compliant CWS are in Connecticut.⁵¹

_{Technical Note: *The vertical axis in the chart above has been shortened, beginning at 85 percent rather than the customary zero. The “Quick Summary” image above addresses CWS Population only. PFAS are a group of man-made chemicals that are widely used in various industrial and consumer products. Exposure to certain PFAS may lead to adverse health outcomes.}

 

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⁴⁷ _{EPA, Drinking Water Performance and Results Report, Government Performance and Results Act (GPRA) tool, GPRA Summary Report and GPRA Violation Report, accessed January 15, 2025; www.epa.gov/ground-water-and-drinking-water/drinking-water-performance-and-results-report.}

⁴⁸_{Department of Public Health (DPH), Freedom of Information Response received March 5, 2025.}

⁴⁹_{DPH, Press Releases, Connecticut Department of Public Health Updates Drinking Water Action Level For Per And Polyfluoroalkyl Substances (PFAS), June 15, 2022; portal.ct.gov/DPH/Newsroom/Press-Releases---2022/PFAS-June-2022.}

⁵⁰_{EPA, The Fifth Unregulated Contaminant Monitoring Rule (UCMR 5) Program Overview Fact Sheet; www.epa.gov/system/files/documents/2022-02/ucmr5-factsheet.pdf.}

⁵¹_{EPA, FY2022 – FY2026 EPA Strategic Plan, March 2022; www.epa.gov/system/files/documents/2022-03/fy-2022-2026-epa-strategic-plan.pdf.}