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Not health advice. Contact your local water utility for concerns.
Data from EPA Water Quality Reports. For official information, contact your water utility or health department.
Water quality data for 4 cities serving 573,281 residents
Fairfield County in Connecticut has an average water quality score of 79/100 (Grade C) based on analysis of 4 municipal water systems. The county's water systems serve approximately 573,281 residents.
Water quality in Fairfield County is fair, with some cities showing room for improvement. Stamford has the best water quality at 85/100.
4 cities ranked by water quality score
| Rank | City | Score | Grade | Population |
|---|---|---|---|---|
| 1 | Stamford Biggest deduction: PFOA detected at up to 4.3 ppt in UCMR5 sampling (2025-12-02), at or above EPA's 4 ppt MCL (−10 pts) | 85 | B | 119,214 |
| 2 | Danbury Biggest deduction: PFOA detected at up to 5.4 ppt in UCMR5 sampling (2025-09-17), at or above EPA's 4 ppt MCL (−10 pts) | 83 | B | 62,055 |
| 3 | Shelton Biggest deduction: PFOA detected at up to 10.9 ppt in UCMR5 sampling (2024-02-20), at or above EPA's 4 ppt MCL (−10 pts) | 74 | C | 351,756 |
| 4 | Norwalk Biggest deduction: PFOA detected at up to 9.5 ppt in UCMR5 sampling (2024-09-10), at or above EPA's 4 ppt MCL (−10 pts) | 73 | C | 40,256 |
Real EPA readings across county water systems (lead: latest 90th percentile; PFAS: UCMR5 2023–2026; others: 2012–2019 averages)
| Contaminant | Avg Level | Max Level | EPA Limit | % of Limit | Cities |
|---|---|---|---|---|---|
| PFAS (PFOA/PFOS max, UCMR5) | 7.95 ppt | 11.2 ppt | 4 ppt | 198.8% | 4 |
| TTHM (2012–2019 avg) | 45.433 ug/L | 51.787 ug/L | 80 ug/L | 56.8% | 4 |
| HAA5 (2012–2019 avg) | 27.566 ug/L | 35.997 ug/L | 60 ug/L | 45.9% | 4 |
| Fluoride (2012–2019 avg) | 0.703 mg/L | 0.765 mg/L | 4 mg/L | 17.6% | 4 |
| Nitrate (2012–2019 avg) | 0.565 mg/L | 1.04 mg/L | 10 mg/L | 5.7% | 4 |
| Lead (90th percentile) | 0.75 ppb | 3 ppb | 15 ppb | 5% | 4 |
| Arsenic (2012–2019 avg) | 0 ug/L | 0 ug/L | 10 ug/L | 0% | 4 |
| Radium (2012–2019 avg) | 0 pCi/L | 0 pCi/L | 5 pCi/L | 0% | 4 |
Recent violations across county water systems
Health-based: Treatment technique — Monthly Turbidity Exceed (Enhanced SWTR) - Interim Enhanced Surface Water Treatment Rule
6/30/2021
Monitoring & reporting — Monitoring and Reporting (DBP) - Total Haloacetic Acids (HAA5)
9/30/2021
Showing 10 of 20 recent violations
Water quality in Fairfield County, Connecticut reflects the region's unique combination of water sources, treatment infrastructure, and environmental factors. Our comprehensive analysis examines 4 municipal water systems serving a combined population of over 573,281 residents.
The county shows moderate water quality performance, with scores ranging from 73/100 in Norwalk to 85/100 in Stamford. This 12-point spread indicates relatively consistent water quality standards across municipal systems.
The most prevalent contaminants detected across Fairfield County water systems include PFAS (PFOA/PFOS max, UCMR5), TTHM (2012–2019 avg), HAA5 (2012–2019 avg). At least one reading averages above 50% of its EPA limit across the county's systems, worth attention from residents and utilities.
Water quality in Fairfield County is fair but shows room for improvement. Residents in cities scoring below 70 should consider water filtration, particularly for drinking and cooking. Check your specific city's report above for personalized recommendations.
Fairfield County has an average water quality score of 79/100 (Grade C) based on analysis of 4 municipal water systems serving 573,281 residents.
Stamford has the highest water quality score in Fairfield County at 85/100. View the detailed report for Stamford.
Given the water quality variation across Fairfield County, we recommend reviewing your specific city's water quality report. 0 cities have scores below 70, where filtration is particularly recommended.
Click on any city in the rankings table above to view its detailed water quality report, including contaminant levels, EPA compliance history, and filter recommendations.