Forever Chemicals
Maybe you're moving across the country to California, maybe you've lived here for years and want to understand your own long-term exposure, or maybe you're just curious what's beneath your neighborhood. Either way, the office behind the rules has a name: the State Water Resources Control Board, which runs drinking-water oversight through its Division of Drinking Water and is among the states that pushed on PFAS ahead of the federal rule. The figures below come from federal testing, not from us, and they don't declare any tap safe or unsafe. They're a record worth reviewing when you're evaluating an address.
EPA's UCMR 5 program (2021–2024) tested 50 public water systems in California for 29 PFAS compounds; 1 reported at least one detection and none exceeded the 2024 federal limit of 4 ppt for PFOA/PFOS (a 2% detection rate). Detections vary by water system — check the utility serving a specific California address.
California's drinking-water rules are administered by the State Water Resources Control Board, through its Division of Drinking Water, which oversees public water systems statewide. California is among the states that moved early on PFAS: rather than waiting solely on the federal rule, the Water Board set its own notification and response levels that prompted utilities to test and act ahead of the April 2024 federal limits. For residents, that tends to mean a more forward-leaning posture layered on top of the federal limits the Board administers — a state that, characteristically, didn't wait to be told.
Numbers below come straight from EPA UCMR 5 monitoring (2021–2024). Every public water system in Californiaserving more than 3,300 people had to test for 29 different PFAS — here's what they reported.
50
Water systems tested
UCMR 5 (2021–2024)
1
Systems with any PFAS detected
2% detection rate
0
Systems exceeding 2024 MCL
Above 4 ppt PFOA/PFOS
6
Distinct PFAS compounds detected
Of 29 monitored under UCMR 5
0
TRI-reporting PFAS facilities
EPA Toxics Release Inventory 2024
11
DoD PFAS installations
Military PFAS contamination sites
Red triangles are military installations the Department of Defense has flagged for PFAS from firefighting foam. Orange dots are industrial facilities that reported PFAS to the EPA Toxics Release Inventory. If your future home sits near a cluster, that's a conversation worth having with the seller or landlord.
These are the Californiautilities where EPA testing found PFAS the most often or at the highest levels. Being on this list doesn't automatically mean today's tap water is unsafe — some systems have added treatment since these samples were taken — but it means a conversation with the utility is worth having before you move in.
| Water system | Detections | Max value (ng/L) | vs 2024 MCL |
|---|---|---|---|
| DOWNEY - CITY, WATER DEPT. | 6 | 0.02 | Below MCL |
PFAS isn't one chemical — it's a family of thousands. Here are the specific compounds EPA picked up most often across California water systems. PFOA and PFOS are the two with the strictest federal limits (4 parts per trillion).
For decades the military trained with AFFF firefighting foam loaded with PFAS. It soaked into soil and groundwater and, in many places, traveled miles. If you're house-hunting near any of these California installations, the address report will tell you exactly how close.
ALAMEDA NAS
Navy
Barstow MCLB
Navy
Castle AFB
Air Force
Former Castle AFB
Air Force
Former George AFB
Air Force
Former March AFB
Air Force
Former Mather AFB
Air Force
March AFB
Air Force
Mather AFB
Air Force
Travis AFB
Air Force
Treasure Island NS
Navy
Looking at a specific Californiacity? Each page below pulls the same federal data narrowed to that water system — useful whether you're relocating, buying, organizing your neighborhood around getting cleaner water, or just trying to find out what's in the tap and what's around you.
Here's how to read what the records show without overreading them. EPA's UCMR 5 round tested for 29 PFAS compounds from 2021 through 2024, but only at public systems serving more than about 3,300 people. California has many small and rural systems, plus plenty of private wells, that weren't required to test — so a quiet result above can mean "no one was obligated to look," not "clean." A detection is a snapshot from its sampling window, not a guarantee about today's tap, especially in a state that has pressed utilities to add treatment. The State Water Board offers well-testing guidance worth finding. California's appetite for setting its own levels does at least come with its own thicket of acronyms.
Yes. EPA UCMR 5 monitoring (2021–2024) tested 50 public water systems in California; 1 had at least one PFAS detection. Detections vary by water system — check your specific serving utility.
California is among the states that acted on PFAS ahead of the federal rule. The State Water Resources Control Board set its own notification and response levels that prompted utilities to test and respond, layered on top of the federal limits it administers, including the April 2024 caps of 4 parts per trillion for PFOA and PFOS.
The State Water Resources Control Board, through its Division of Drinking Water, oversees public water systems in California and has tended toward a forward-leaning PFAS posture — setting notification and response levels and pressing utilities to monitor — alongside enforcing the federal limits.
Drinking water in California is overseen by the State Water Resources Control Board through its Division of Drinking Water. It's the state office responsible for public water system standards and the one to reach about water quality questions.
Use VetMyAddress to see the PFAS detections reported for the public water system serving any California address, alongside nearby military bases and industrial PFAS sources. The data comes from EPA UCMR 5, EPA TRI, and the DoD PFAS installation report.
In April 2024 the EPA set the first enforceable federal limits for PFAS in drinking water: 4 parts per trillion for PFOA and PFOS, and 10 ppt each for PFHxS, PFNA, and HFPO-DA (GenX), plus a Hazard Index for certain mixtures. Public water systems must complete initial monitoring by 2027 and come into compliance after that.
No. The federal limits apply to public water systems. Private well owners are responsible for their own testing and treatment, which is especially worth doing near a known PFAS source like a military base or industrial site.
State numbers tell you the pattern. An address report tells you what's actually in the water at yourkitchen sink — the matched utility, the PFAS detections on file, and every military or industrial source nearby. Whether it's for your family, your neighbors, or peace of mind.
Data sources: EPA UCMR 5 bulk data · EPA TRI 2024 · DoD PFAS installation report