Monitoring Violations
Water systems with monitoring violations, meaning they failed to test their water as required by EPA regulations. Missing tests may hide contamination.
Systems With Monitoring Violations (44)
City of Jackson
Jackson, Mississippi
Thornton City Of
Thornton, Colorado
Gru - Murphree Wtp
Gainesville, Florida
Philadelphia Water Department
Philadelphia, Pennsylvania
Chicago
Chicago, Illinois
Cleveland Public Water System
Cleveland, Ohio
Denver Water Board
Denver, Colorado
Wvawc - Huntington Dist
Charleston, West Virginia
Saint Paul Regional Water Services
St. Paul, Minnesota
Salt Lake City Water System
Salt Lake City, Utah
Liberty Utilities New York - Lynbrook
Merrick, New York
Mesa City Of
Mesa, Arizona
Greensboro, City Of
Greensboro, North Carolina
Newark Water Department
Newark, New Jersey
Gilbert, Town Of
Gilbert, Arizona
Waterbury Water Department
Waterbury, Connecticut
Medford Water Commission
Medford, Oregon
Citizens Water - Indianapolis
Indianapolis, Indiana
Metropolitan Utilities District
Omaha, Nebraska
Winston-Salem, City Of
Pfafftown, North Carolina
Kalamazoo
Kalamazoo, Michigan
Berkeley County Pswd-Potomac River
Martinsburg, West Virginia
North Fulton County
Alpharetta, Georgia
New Orleans Carrollton Water Works
New Orleans, Louisiana
Clermont Public Water System
Batavia, Ohio
Lowell Regional Water Utility
Lowell, Massachusetts
Hardin County Water District #2
Elizabethtown, Kentucky
Jea Major Grid
Jacksonville, Florida
Metropolitan District Commission
Hartford, Connecticut
Durham, City Of
Durham, North Carolina
Ann Arbor
Ann Arbor, Michigan
Springfield Pws
Springfield, Missouri
Tuscaloosa Water & Sewer
Tuscaloosa, Alabama
St George City Water System
St George City, Utah
Warren County Water District
Bowling Green, Kentucky
Santa Fe Water System (city Of)
Santa Fe, New Mexico
Aqua Pa Main System
Bryn Mawr, Pennsylvania
Mcwa
Rochester, New York
Wichita, City Of
Wichita, Kansas
Aquarion-Eastern Fairfield County
Shelton, Connecticut
Nj American Water - Western
Delran, New Jersey
Wildwood City Water Department
Rio Grande, New Jersey
Rochester City
Rochester, New York
Roswell Municipal Water System
Roswell, New Mexico
Frequently Asked Questions
A monitoring violation means the water system failed to test its water as frequently as required by EPA regulations. While not an immediate health threat, missing tests means contamination could go undetected. Systems with monitoring violations may be hiding water quality problems.
44 water systems currently have monitoring violations, affecting 18,701,284 people. These systems have accumulated 232 total violations.
Monitoring violations mean your water may not be tested enough. Contact your water utility and ask about their testing schedule. You can also get your water independently tested through a state-certified lab.
Source: EPA Ground Water and Drinking Water, 2026.