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State profile · EPA SDWIS + UCMR5

Connecticut Drinking Water Quality

2,332 public water systems serve 2,886,005 people across Connecticut, with every Safe Drinking Water Act violation and UCMR5 PFAS result on record.

2,332
Water systems
206,662
Total violations
94%
Systems w/ a violation
63.5%
PFAS detection rate

The verdict

Across Connecticut, 2,193 of 2,332 water systems (94.0%) carry at least one EPA violation, and 40 of 63 UCMR5-tested systems show PFAS.

206,662
Total EPA violations on record
11%
Health-based (MCL / treatment)
94.0%
Systems with ≥1 violation
63.5%
UCMR5 PFAS detection rate
Water Systems
2,332
Total Violations
206,662
Violation Rate
94%
PFAS Detection
63.5%
40 of 63 tested

Violation Composition

How Connecticut's 206,662 violations break down by type, per EPA SDWIS classification.

Health-based (21,779) Monitoring/Reporting (184,883)
Metric Value Share
Public water systems2,332-
Population served2,886,005-
Total violations206,662100%
Health-based violations21,77910.5%
Systems with violations2,19394.0%
PFAS detection rate40 of 6363.5%

Health-based violations indicate the contaminant exceeded an EPA Maximum Contaminant Level (MCL) or treatment-technique requirement. Monitoring/reporting violations indicate procedural issues (missed tests, late reports) - not necessarily a contamination event.

Largest Water Systems

Regional Water Authority
New Haven, CT · 418,900 served
62 violations
Metropolitan District Commission
Hartford, CT · 390,887 served
3 violations
Aquarion-Eastern Fairfield County
Shelton, CT · 351,756 served
585 violations
Aquarion-Stamford
Shelton, CT · 119,214 served
136 violations
Waterbury Water Department
Waterbury, CT · 107,271 served
35 violations
Ctwc - Northern Reg-Western System
Clinton, CT · 101,313 served
406 violations
New Britain Water Department
New Britain, CT · 73,534 served
34 violations
Danbury Water Department
Danbury, CT · 62,055 served
326 violations
Meriden Water Division
Meriden, CT · 58,441 served
119 violations
Aquarion-Greenwich
Shelton, CT · 53,297 served
114 violations
Bristol Water Department
Bristol, CT · 52,079 served
269 violations
Manchester Water Department
Manchester, CT · 51,198 served
31 violations
Southington Water Department
Southington, CT · 43,069 served
1,028 violations
South Norwalk Electric & Water
Wilton, CT · 42,000 served
215 violations
Middletown Water Department
Middletown, CT · 41,019 served
26 violations
Norwalk First Taxing District
Norwalk, CT · 40,256 served
6 violations
Torrington Water Company
Shelton, CT · 37,915 served
105 violations
Wallingford Water Department
Wallingford, CT · 37,267 served
188 violations
Norwich Public Utilities
Norwich, CT · 36,163 served
97 violations
Ctwc - Shoreline Region-Guilford System
Clinton, CT · 33,975 served
575 violations

Most Violations

#1 27 Maple Drive Monroe
5,163
#2 Garden Lane Apartments Bantam
1,470
#3 Fawn Ridge Association Inc. Charlton
1,282
#4 Oakridge Village Forest Hills
1,162
#5 125-131 Bradley Road - Woodbridge Woodbridge
1,147
#6 Yeshiva of Waterbury-Durham Campus Waterbury
1,081
#7 4 West Granby Road Granby
1,032
#8 Southington Water Department Southington
1,028
#9 Lyme Academy Apartments,llc Torrington
935
#10 Thompson Hill Water Co - Paula Lane Div Thompson
885
#11 Oakdale Manor Water Association Southbury
856
#12 890 Boston Turnpike Tolland
855
#13 31 Old Route Seven Bethel
794
#14 The Learning Den West Hartford
748
#15 Cadence Academy Canton
738

Counties in Connecticut

Hartford
219 systems · 836,032 served · 20,244 violations
Fairfield
336 systems · 779,265 served · 42,084 violations
New Haven
212 systems · 723,250 served · 17,543 violations
New London
396 systems · 209,068 served · 34,737 violations
Litchfield
345 systems · 117,396 served · 27,780 violations
Middlesex
276 systems · 97,390 served · 25,593 violations
Windham
255 systems · 63,884 served · 21,628 violations
Tolland
293 systems · 59,720 served · 17,053 violations
View all 2,332 systems in Connecticut →

Drinking Water Guides

Is Your Tap Water Safe?

How to interpret water quality reports and know when to take action.
PFAS in Drinking Water

What forever chemicals are, EPA testing results, and 2024 standards.
Check Your Water System

Step-by-step guide to finding and understanding your local water data.

Frequently Asked Questions

How many water systems are in Connecticut? ▼
Connecticut has 2,332 public water systems serving approximately 2,886,005 people. These include community water systems, non-transient non-community systems, and transient non-community systems regulated under the Safe Drinking Water Act.
How many drinking water violations are in Connecticut? ▼
Connecticut has 206,662 total drinking water violations on record, with 21,779 classified as health-based violations. 94.0% of water systems in the state have at least one violation.
Has PFAS been found in Connecticut drinking water? ▼
Of 63 water systems tested for PFAS in Connecticut, 40 had PFAS detected, a 63.5% detection rate. PFAS are persistent "forever chemicals" that do not break down in the environment.
What is the violation rate for Connecticut water systems? ▼
Connecticut's violation rate is 94%. This measures the percentage of public water systems that have at least one recorded violation in the EPA SDWIS database, including both health-based and monitoring/reporting violations.
Where does this Connecticut water data come from? ▼
All drinking water data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS is the federal database that tracks compliance for all public water systems regulated under the Safe Drinking Water Act.

Data Sources & Methodology

Drinking water violation data from the EPA Safe Drinking Water Information System (SDWIS). PFAS testing data from the UCMR5 monitoring program. SDWIS tracks all public water systems regulated under the Safe Drinking Water Act.

Read our methodology - how this data is sourced, computed, and verified.

Related

All states → | Most violations → | Compare counties →
Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This page draws directly on EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.