Water Systems Directory
Look up any of 19,323 U.S. public water systems by ZIP code or city. EPA violation history, contaminant data, and a safety score for each.
Find your water system
Enter a ZIP code or city to see the public water system that serves it, its EPA compliance history, and safety score.
Largest water systems
New York City System
ANew York · 8,271,000 people
Los Angeles-city, Department of Water & Power
BCalifornia · 3,875,566 people
City of Houston
ATexas · 2,970,543 people
Chicago
BIllinois · 2,721,308 people
San Antonio Water System
ATexas · 2,643,729 people
Mdwasa - Main System
CFlorida · 2,377,460 people
Washington Suburban Sanitary Commission
BMaryland · 1,900,000 people
City of Phoenix
BArizona · 1,695,000 people
City of Baltimore
CMaryland · 1,600,000 people
Philadelphia Water Department
BPennsylvania · 1,600,000 people
Las Vegas Valley Water District
ANevada · 1,539,277 people
East Bay Municipal Utility District
ACalifornia · 1,442,800 people
Most EPA violations on record
Country Glen Townhomes
Pennsylvania · 1,163 violations
Pa American Audubon
Pennsylvania · 862 violations
Bullhead City Mohave
DArizona · 784 violations
Brooksville
Oklahoma · 718 violations
Oilton
Oklahoma · 605 violations
Prague
Oklahoma · 586 violations
Frankfort Public Service District
West Virginia · 456 violations
Forest Park Tc
Alaska · 432 violations
Country Mhp
Oklahoma · 414 violations
Nico Tyme Water Coop
Texas · 329 violations
Seven Estates
Texas · 325 violations
Hominy
Oklahoma · 290 violations
Browse by state
Every public water system, grouped by the state it serves.
Data: U.S. Environmental Protection Agency (EPA) SDWIS
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