Is Tap Water Safe in the US? PFAS Levels by State
45% of US tap water contains detectable PFAS. Here's what EPA and USGS data shows - by state and by water source.
- 45% of US tap water contains detectable PFAS (USGS 2023)
- EPA set limits of 4.0 parts per trillion for PFOA and PFOS in 2024; in May 2026 it proposed keeping those two and rescinding the limits for four other PFAS
- Highest share of tested water systems with PFOA or PFOS averaging above 4.0 ppt: Connecticut, New Jersey, Florida (EPA UCMR 5)
- Lowest, among states with 50+ systems tested: Iowa, Arkansas, Louisiana (EPA UCMR 5)
PFAS results by state (EPA UCMR 5)
Between 2023 and 2025 about 10,000 public water systems tested for PFAS under EPA's UCMR 5. The table shows the states where the largest share of tested systems had a PFOA or PFOS average above the 4.0 ppt limit, calculated the way EPA did in its July 2026 data summary. Two cautions from EPA itself: these results do not show compliance or noncompliance with the limits, and only a sample of the smallest systems took part, so a state figure is not an estimate for every system in it.
| State | Systems with full results | PFOA or PFOS average above 4.0 ppt |
|---|---|---|
| Connecticut | 63 | 28 (44.4%) |
| New Jersey | 258 | 114 (44.2%) |
| Florida | 394 | 127 (32.2%) |
| South Carolina | 154 | 49 (31.8%) |
| Massachusetts | 260 | 75 (28.8%) |
| North Carolina | 277 | 68 (24.5%) |
| Pennsylvania | 386 | 93 (24.1%) |
| California | 685 | 129 (18.8%) |
| Alabama | 302 | 56 (18.5%) |
| Maryland | 82 | 15 (18.3%) |
At the other end, among states with at least 50 systems tested: Iowa 0%, Arkansas 0%, Louisiana 0.4%, New Mexico 1.4%, Utah 1.6%. A low state figure says nothing about your own system. Look up your water system by ZIP code for its own results, and the full table for every state.
City water vs well water
City water is treated and tested by utilities - results are published in annual Consumer Confidence Reports. Well water is untreated and untested by default. Well owners are responsible for their own testing.
- PFAS from industrial discharge
- Lead from old pipes
- Chlorine & chloramines
- Disinfection byproducts
- PFAS from groundwater
- Bacteria & coliform
- Iron & manganese
- Nitrates from agriculture
How to check your specific water
Three ways to check PFAS and contaminant levels in your area:
What to do if PFAS is detected
If your utility reports PFAS above the EPA limit of 4 ppt - or if you want protection regardless - a filter listed for PFOA and PFOS by name, under NSF/ANSI 53 or 58, is the most reliable solution available for home use.
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