PFAS Contamination in California: 653 ZIP Codes Tested
653 ZIPs tested · 245 exceeding limits (38%)
Data source: EPA UCMR 3/5, SDWIS, ECHO, DOD Last verified: 2026-06-03
PFAS Contamination Summary
| Metric | Value |
|---|---|
| ZIP codes with PFAS detections | 653 |
| ZIP codes exceeding EPA limits | 245 (38%) |
| Superfund sites | 99 |
| Military bases linked to PFAS | 88 of 121 |
| Testing coverage | 25% of state ZIP codes |
| Untested ZIP codes | 1,932 |
Most Common PFAS Compounds Detected
| Compound | ZIP Codes with Detections |
|---|---|
| PFHxS | 414 |
| PFPeA | 401 |
| PFOS | 385 |
| PFBA | 356 |
| PFHxA | 352 |
| PFOA | 316 |
Worst-Affected Areas in California
The following ZIP codes have the highest number of PFAS detections in California:
| Rank | ZIP Code | City | PFAS Types | Total Detections | Exceeds EPA Limit |
|---|---|---|---|---|---|
| 1 | 93727 | Fresno | 11 | 260 | Yes |
| 2 | 93704 | Fresno | 10 | 231 | Yes |
| 3 | 93710 | Fresno | 10 | 231 | Yes |
| 4 | 93711 | Fresno | 10 | 231 | Yes |
| 5 | 93720 | Fresno | 10 | 231 | Yes |
| 6 | 93701 | Fresno | 10 | 213 | Yes |
| 7 | 93702 | Fresno | 10 | 213 | Yes |
| 8 | 93703 | Fresno | 10 | 213 | Yes |
| 9 | 93705 | Fresno | 10 | 213 | Yes |
| 10 | 93706 | Fresno | 10 | 213 | Yes |
Check your ZIP code on our PFAS map to see if your area is affected.
Sources of PFAS Contamination in California
PFAS contamination in California comes from several key sources:
Military Installations
88 military bases in California are linked to PFAS contamination, primarily from the use of aqueous film-forming foam (AFFF) in firefighting training exercises.
Key installations include:
- George Air Force Base
- March Air Reserve Base
- El Toro Marine Corps Air Station
- Castle Air Force Base
Superfund Sites
California has 99 Superfund sites that may contribute to PFAS contamination. Major sites include:
- EXIDE TECHNOLOGIES VERNON
- COOPER DRUM CO
- JERVIS B WEBB CO
- SOUTHERN AVENUE INDUSTRIAL AREA
- PEMACO MAYWOOD
Industrial and Municipal Sources
Beyond military and Superfund sites, PFAS contamination in California also stems from:
- Industrial facilities that manufactured or used PFAS-containing products
- Airports that used AFFF firefighting foam
- Wastewater treatment plants that received PFAS-laden industrial discharge
- Landfills accepting PFAS-containing consumer products
California PFAS Regulations
California has established its own PFAS drinking water standards:
State limits: Notification levels: PFOA 5.1 ppt, PFOS 6.5 ppt; Response levels: PFOA 10 ppt, PFOS 40 ppt
California has notification and response levels, with enforceable MCLs under development.
In addition to state limits, the federal EPA PFAS rule (April 2024) sets MCLs of 4 ppt for PFOA and PFOS, with compliance required by 2029.
Testing Gaps
Only 25% of ZIP codes in California have been tested for PFAS. That leaves 1,932 ZIP codes with no public PFAS data.
The EPA requires all public water systems to complete PFAS monitoring by 2027. Until then, residents in untested areas may want to consider independent water testing or a certified PFAS filter.
What California Residents Can Do
1. Check Your Water
Enter your ZIP code on ZipCheckup to see PFAS detections, violations, and health risk scores for your area.
2. Get Your Water Tested
If your ZIP code has PFAS detections or is in an untested area, consider a certified lab test. Look for labs accredited under EPA Method 533 or 537.1. Home test kits cost $150-$350 and cover the six regulated PFAS compounds.
3. Install a Certified Filter
The most effective home treatment options for PFAS removal:
- Reverse osmosis (RO) systems remove 90-99% of PFAS (NSF 58 certified)
- Granular activated carbon (GAC) filters remove 60-95% depending on the compound (NSF 53 certified)
- Ion exchange systems are effective for short-chain PFAS
Use our Filter Matcher tool to find NSF-certified filters that remove PFAS.
4. Check for Lead Risk Too
Many areas with PFAS contamination also face lead service line risks. Use our Lead Risk Calculator to assess your home's lead exposure risk.
Frequently Asked Questions
How many ZIP codes in California have PFAS in their water?
Based on EPA data, 653 ZIP codes in California have detectable PFAS in their public water supply. Of those, 245 (38%) exceed the federal MCL of 4 ppt for PFOA or PFOS.
Is my water safe to drink in California?
It depends on your location. 245 ZIP codes in California exceed federal PFAS limits. Enter your ZIP code on ZipCheckup to see your area's specific results. Even if your water meets current standards, you may want to use a certified filter as PFAS accumulate in the body over time.
Does California have its own PFAS limits?
Yes. California has notification and response levels, with enforceable MCLs under development. State limits: Notification levels: PFOA 5.1 ppt, PFOS 6.5 ppt; Response levels: PFOA 10 ppt, PFOS 40 ppt. These operate alongside the federal EPA standard of 4 ppt for PFOA and PFOS.
What is the best water filter for PFAS in California?
Reverse osmosis (RO) systems certified to NSF 58 are the most effective option, removing 90-99% of PFAS compounds. Granular activated carbon (GAC) filters certified to NSF 53 also reduce PFAS significantly. Use the ZipCheckup Filter Matcher tool to find certified filters for your specific contaminants.
Where does PFAS contamination in California come from?
The primary sources include 88 military bases that used AFFF firefighting foam, 99 Superfund sites, industrial facilities, airports, and wastewater treatment plants. PFAS are also found in landfill leachate from consumer products containing these chemicals.
Why hasn't my area been tested for PFAS?
Only 25% of ZIP codes in California have public PFAS testing data. The EPA requires all public water systems to complete PFAS monitoring by 2027 under the new federal rule. Until then, you can get independent lab testing (EPA Method 533 or 537.1) for $150-$350.