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WaterSafety

Water Systems with Most Violations (2026)

The worst offender has 113 total violations and exceedances. These water systems have accumulated the most health violations and contaminant exceedances on record.

#Water SystemHealth ViolationsGrade
1City of Jackson
Jackson, MS
100F
2Shreveport Water System
Shreveport, LA
76F
3Newark Water Department
Newark, NJ
22F
4Springfield Water and Sewer Commission
Springfield, MA
27F
5Tuscaloosa Water & Sewer
Tuscaloosa, AL
6F
6Atlanta
Atlanta, GA
5F
7Sioux City Water Supply
Sioux City, IA
10F
8Mobile, Bd. Of W&s Comm. Of the City Of
Mobile, AL
4F
9Bjw&sa (0720003)
Okatie, SC
4F
10Papillion, City Of
Papillion, NE
3F
11Liberty Utilities New York - Lynbrook
Merrick, NY
6F
12Kearney, City Of
Kearney, NE
3F
13Columbus Public Water System
Columbus, OH
3F
14Las Cruces Municipal Water System
Las Cruces, NM
6F
15Gilbert, Town Of
Gilbert, AZ
3F
16Columbia City of (sc4010001)
Columbia, SC
3F
17Kalamazoo
Kalamazoo, MI
4F
18City of Baltimore
Baltimore, MD
3F
19Clermont Public Water System
Batavia, OH
2F
20Fort Wayne - 3 Rivers Filtration Plant
Fort Wayne, IN
3F
21Lowell Regional Water Utility
Lowell, MA
3F
22Salt Lake City Water System
Salt Lake City, UT
2F
23New Orleans Carrollton Water Works
New Orleans, LA
2F
24Aqua Pa Main System
Bryn Mawr, PA
2F
25Roswell Municipal Water System
Roswell, NM
2F
26Phoenix City Of
Phoenix, AZ
2D
27Des Moines Water Works
Des Moines, IA
2D
28Chandler City Of
Chandler, AZ
1D
29Topeka, City Of
Topeka, KS
1D
30Glen Burnie-Broadneck
Millersville, MD
1D
31Santa Fe Water System (city Of)
Santa Fe, NM
1D
32Cocoa, City Of
Cocoa, FL
1C
33Cicero
Cicero, IL
1C
34Veolia Water New Jersey Hackensack
Haworth, NJ
1C
35Jersey City Mua
Hoboken, NJ
1C
36Norman Utilities Authority
Norman, OK
1C
37Kansas City Pws
Kansas City, MO
1C
38Portland Water Bureau
Portland, OR
1C
39Fort Smith Water Utilities
Fort Smith, AR
1C
40Mcwa
Rochester, NY
1B
41Rochester City
Rochester, NY
1B
42Boston Water and Sewer Commission (mwra)
Boston, MA
1B
43Madison Water Utility
Madison, WI
1B
44Philadelphia Water Department
Philadelphia, PA
0C
45Thornton City Of
Thornton, CO
0C
46Gru - Murphree Wtp
Gainesville, FL
0C
47Cleveland Public Water System
Cleveland, OH
0C
48Chicago
Chicago, IL
0C
49Denver Water Board
Denver, CO
0C
50Saint Paul Regional Water Services
St. Paul, MN
0C

Frequently Asked Questions

Health-based violations occur when a contaminant level exceeds the EPA Maximum Contaminant Level (MCL) or when required treatment techniques are not followed. These are the most serious type of drinking water violation.

This ranking includes both active and resolved violations. Check individual system pages for current violation status. Many systems have taken corrective action since violations were recorded.

Request your system's annual Consumer Confidence Report (CCR) for current water quality data. Consider an NSF-certified water filter for extra protection, especially if violations are recent or ongoing.

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