54.2 million
people on systems with PFAS above the 2024 federal limits
1,099
water systems above a PFAS limit
9,934
systems EPA tested for 29 PFAS
49,172
community water systems covered
Largest systems with PFAS above the limit
A result above the limit is not a violation yet: systems have until 2029 to meet the 2024 PFAS limits, and many are already adding treatment.
- MDWASA – Main System2.4 million people · Groundwater · FloridaPFOA above limitAlso: PFOS above limit · PFHxS detected · PFNA detected
- Philadelphia Water Department1.6 million people · Surface water · PennsylvaniaPFOA above limitAlso: PFOS above limit · PFNA detected
- Fairfax County Water Authority1.1 million people · Surface water · VirginiaPFOA above limitAlso: PFOS detected
- Suffolk County Water Authority1.1 million people · Groundwater · New YorkPFOA above limitAlso: PFOS above limit · PFHxS detected · PFNA detected · 1 health-based violation since 2016
- PRASA Metropolitano1.1 million people · Surface water · Puerto RicoPFOS above limitAlso: Total trihalomethanes (TTHM) violations · Haloacetic acids (HAA5) violations · Coliform bacteria violations
- City of Fort Worth955,900 people · Surface water · TexasPFOA above limitAlso: PFOS above limit · PFHxS above limit · PFAS Hazard Index above limit · 1 health-based violation since 2016
Largest cities
- New York, NY
- Los Angeles, CA
- Chicago, IL
- Houston, TX
- Phoenix, AZ
- Philadelphia, PA
- San Antonio, TX
- San Diego, CA
- Dallas, TX
- Fort Worth, TX
- Jacksonville, FL
- Austin, TX
- San Jose, CA
- Charlotte, NC
- Columbus, OH
- Indianapolis, IN
- San Francisco, CA
- Hempstead, NY
- Seattle, WA
- Denver, CO
- Nashville, TN
- Oklahoma City, OK
- Washington, DC
- El Paso, TX
- Las Vegas, NV
- Boston, MA
- Detroit, MI
- Portland, OR
- Memphis, TN
- Baltimore, MD
- Milwaukee, WI
- Albuquerque, NM
- Fresno, CA
- Tucson, AZ
- Sacramento, CA
- Atlanta, GA
- Kansas City, MO
- Mesa, AZ
- Raleigh, NC
- Brookhaven, NY
- Colorado Springs, CO
- Miami, FL
- Omaha, NE
- Virginia Beach, VA
- Long Beach, CA
- Oakland, CA
- Minneapolis, MN
- Bakersfield, CA
- Tulsa, OK
- Tampa, FL
Contaminants
Rankings
- Highest PFOA/PFOS (10,000+ people)Large water systems with the highest PFOA or PFOS
- PFAS over the limit, by people servedBiggest water systems with PFAS above the federal limit
- Most health-based violationsWater systems with the most health-based violations since 2016
- Highest lead (10,000+ people)Large water systems with the highest lead levels
- Highest lithiumWater systems with the most lithium
Browse by state
- Alabama
- Alaska
- American Samoa
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Delaware
- District of Columbia
- Florida
- Georgia
- Guam
- Hawaii
- Idaho
- Illinois
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Hampshire
- New Jersey
- New Mexico
- New York
- North Carolina
- North Dakota
- Northern Mariana Islands
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- Puerto Rico
- Rhode Island
- South Carolina
- South Dakota
- Tennessee
- Texas
- U.S. Virgin Islands
- Utah
- Vermont
- Virginia
- Washington
- West Virginia
- Wisconsin
- Wyoming
What this data can and can’t tell you
- A detection is not a violation. PFAS limits apply from 2029, and EPA says its UCMR 5 results do not indicate compliance.
- Not tested is not the same as not detected. EPA tested every system serving 3,300+ people for PFAS, and only a sample of smaller ones.
- Your own pipes matter. Lead comes from service lines and plumbing, so the utility's number can't tell you what's at your tap.
- On a private well? Public data doesn't cover wells. Testing a well.
Data: EPA SDWIS (2026Q3) and UCMR 5 final (Oct 15, 2026). Data and method.