Is Your Tap Water
Safe to Drink?
We grade every public water system in America A through F. Search 190 water systems serving 73,281,703 people, see violation history, contaminant levels, and enforcement actions that never make the news.
National Grade Distribution
How America's water systems score on our A-F safety scale.
Worst Water Systems
Lowest Water Safety Scores in our database
City of Jackson
Jackson, Mississippi
Newark Water Department
Newark, New Jersey
Tuscaloosa Water & Sewer
Tuscaloosa, Alabama
Atlanta
Atlanta, Georgia
Shreveport Water System
Shreveport, Louisiana
Mobile, Bd. Of W&s Comm. Of the City Of
Mobile, Alabama
Best Water Systems
Highest Water Safety Scores, clean records, zero violations
East Bay MUD
Oakland, California
Alameda County Water District
Fremont, California
CWS - Bakersfield
San Jose, California
Contra Costa Water District
Concord, California
Dallas Water Utility
Dallas, Texas
City of Plano
Plano, Texas
Contaminants We Track
28 EPA-regulated contaminants monitored across all water systems. Click any contaminant for health effects, MCL limits, and filter recommendations.
Total Trihalomethanes
Disinfection Byproduct
Haloacetic Acids (haa5)
Disinfection Byproduct
PFOS/PFOA (PFAS)
Synthetic Chemical
Lead
Inorganic Chemical
Nitrate
Inorganic Chemical
Chlorine (Disinfectant)
Disinfectant
Browse by State
Water quality data for 38 states and territories.
Alabama
625 systems · 2 with violations
Arizona
625 systems · 4 with violations
Arkansas
965 systems · 1 with violations
California
995 systems · 0 with violations
Colorado
795 systems · 2 with violations
Connecticut
825 systems · 3 with violations
Florida
825 systems · 3 with violations
Georgia
775 systems · 2 with violations
Illinois
855 systems · 2 with violations
Indiana
865 systems · 2 with violations
Iowa
765 systems · 2 with violations
Kansas
845 systems · 2 with violations
Kentucky
895 systems · 2 with violations
Louisiana
735 systems · 2 with violations
Maryland
745 systems · 2 with violations
Massachusetts
745 systems · 3 with violations
Michigan
805 systems · 2 with violations
Minnesota
875 systems · 1 with violations
Mississippi
705 systems · 1 with violations
Missouri
865 systems · 2 with violations
Nebraska
705 systems · 3 with violations
Nevada
925 systems · 0 with violations
New Jersey
615 systems · 5 with violations
New Mexico
685 systems · 3 with violations
New York
745 systems · 3 with violations
North Carolina
825 systems · 3 with violations
Ohio
715 systems · 3 with violations
Oklahoma
825 systems · 1 with violations
Oregon
855 systems · 2 with violations
Pennsylvania
865 systems · 2 with violations
South Carolina
715 systems · 2 with violations
Tennessee
945 systems · 0 with violations
Texas
925 systems · 0 with violations
Utah
755 systems · 2 with violations
Virginia
975 systems · 0 with violations
Washington
985 systems · 0 with violations
West Virginia
855 systems · 2 with violations
Wisconsin
925 systems · 1 with violations
Compare Water Systems
Side-by-side comparison of safety scores, contaminant levels, and violation history. Compare your water system with any other in America.
Start comparing →Research & Guides
Deep dives on PFAS, lead, microplastics, and more. Data-driven analysis using EPA records to answer the questions that matter about your drinking water.
Read the blog →Largest Water Systems
The biggest water systems in America by population served, search yours above for the full report.
Chicago
Chicago, Illinois
San Antonio Water System
San Antonio, Texas
Washington Suburban Sanitary Commission
Laurel, Maryland
Phoenix City Of
Phoenix, Arizona
Philadelphia Water Department
Philadelphia, Pennsylvania
City of Baltimore
Baltimore, Maryland
Las Vegas Valley Water District
Las Vegas, Nevada
East Bay MUD
Oakland, California
Dallas Water Utility
Dallas, Texas
Cleveland Public Water System
Cleveland, Ohio
Columbus Public Water System
Columbus, Ohio
Denver Water Board
Denver, Colorado
Charlotte Water
Charlotte, North Carolina
Fairfax County Water Authority
Herndon, Virginia
Mo American St Louis St Charles Counties
Chesterfield, Missouri
Frequently Asked Questions
What is a Water Safety Score?
The Water Safety Score is our proprietary grading system that rates water systems from A (safest) to F (most concerns). It weighs four factors: health-based violations (40%), contaminant exceedances (30%), enforcement history (20%), and monitoring violations (10%). Scores use EPA SDWIS data from the last 10 years.
Where does this data come from?
All data comes from the EPA's Safe Drinking Water Information System (SDWIS), which tracks every public water system in the United States. The EPA publishes this data quarterly, and we process, normalize, and score it to make it searchable and comparable.
What should I do if my water system has a low score?
Request your utility's Consumer Confidence Report (CCR), get an independent water test from a certified lab, and consider a certified water filter for the specific contaminants detected. For health-based violations, follow any boil water advisories.
Do you track PFAS and microplastics?
We track PFAS (PFOA/PFOS) using EPA SDWIS violation data. Microplastics are not yet regulated under the Safe Drinking Water Act, so there is no official compliance data, but our research covers what we know and how to reduce exposure.
What is the maximum contaminant level (MCL) for arsenic?
The EPA's Maximum Contaminant Level (MCL) for arsenic in drinking water is 10 parts per billion (ppb). This standard has been in effect since 2006. Any water system exceeding this limit is in violation. Arsenic is naturally occurring in groundwater and is a known carcinogen at high levels. Search your water system to see if arsenic levels have been flagged.
Is my city's water safe to drink?
Water safety varies by water system, not just city. Many cities have multiple water providers with different quality records. Search your zip code or water system name to see the specific Water Safety Score, violation history, and contaminant data for the water system that serves your address.