PFAS in California: 653 ZIP Codes Linked to PFAS Detections
653 ZIPs linked to PFAS sampling ยท 245 with samples above federal MCL levels (38%)
Data source: EPA UCMR 3/5, SDWIS, ECHO, DOD
ZipCheckup's PFAS reading for California: 245 of 653 tested ZIP codes (38%) are linked to water systems with a UCMR result above the value of an EPA PFAS MCL, with compliance required from 2029. Separately, the state has 99 Superfund sites (not screened for PFAS) and 88 military sites in Department of Defense PFAS investigations.
PFAS Contamination Summary
| Metric | Value |
|---|---|
| ZIP codes with PFAS detections | 653 |
| ZIP codes with a PFAS sample above an EPA MCL level (MCL takes effect in 2029) | 245 (38%) |
| Superfund sites | 99 |
| Military bases with PFAS records in our data | 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 in California are mapped to water systems with the most reported PFAS detections:
| 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 our PFAS map for reported detections associated with water systems serving your area.
Sources of PFAS Contamination in California
Potential sources of PFAS in California include:
Military Installations
88 military bases in California are linked to PFAS contamination in these records; aqueous film-forming foam (AFFF) used in firefighting training is a possible source at military sites.
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; this count does not establish a link to PFAS in drinking water. 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, other potential PFAS sources in California include:
- Industrial facilities that make or use PFAS-containing products (a potential source)
- Airports that used AFFF firefighting foam
- Wastewater treatment plants, which can receive industrial discharge containing PFAS
- Landfills, which can receive PFAS-containing consumer products
California PFAS Regulations
California has set its own PFAS drinking water levels (enforceable standards or advisory levels, as listed below):
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 public PFAS testing data in our records. That leaves 1,932 ZIP codes with no PFAS results mapped in our records.
The EPA requires community and non-transient non-community water systems to complete initial PFAS monitoring by 2027. Until then, residents whose water has no mapped PFAS result may want to consider independent water testing or a filter certified for PFAS reduction.
What California Residents Can Do
1. Check Your Water
Enter your ZIP code on ZipCheckup to see mapped PFAS detections and water-system violation records associated with your area.
2. Get Your Water Tested
If a water system serving your ZIP code has a PFAS detection, or no PFAS result is mapped for your area, consider a certified lab test. Look for a laboratory certified to test drinking water for PFAS using EPA Method 533 or 537.1. Before ordering, check which PFAS compounds a test measures and whether it includes the compounds regulated by EPA.
3. Install a Certified Filter
Home treatment options that can reduce some PFAS:
- Reverse osmosis (RO) systems certified to NSF 58 for PFOA/PFOS reduction
- Granular activated carbon (GAC) filters certified to NSF/ANSI 53 for PFOA/PFOS reduction can reduce those compounds
- 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
Lead service line risk is separate from PFAS results and should be checked on its own. Use our Lead Risk Calculator to assess your home's lead exposure risk.
Frequently Asked Questions
How many ZIP codes in California are linked to water-system PFAS detections?
Based on EPA data, 653 ZIP codes in California are linked to a public water system with a PFAS detection. Of those, 245 (38%) had a PFOA or PFOS sample above the level of the 4 ppt federal MCL, which takes effect in 2029.
Is my water safe to drink in California?
It depends on your location. 245 ZIP codes in California had a PFAS sample above the level of a federal MCL, which takes effect in 2029. Enter your ZIP code on ZipCheckup to see your area's specific results. If PFAS are a concern, consider a filter certified for reduction of the specific PFAS in your water.
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 for PFOA/PFOS reduction are among the most effective options for reducing PFAS. Granular activated carbon (GAC) filters certified to NSF 53 for PFOA/PFOS reduction also reduce PFAS. Use the ZipCheckup Filter Matcher tool to find certified filters for your specific contaminants.
Where does PFAS contamination in California come from?
Potential PFAS source types 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 is there no PFAS result mapped to my area?
Public PFAS monitoring results in our records cover water systems mapped to only 25% of ZIP codes in California. The EPA requires community and non-transient non-community water systems to complete initial PFAS monitoring by 2027 under the federal PFAS rule. Until then, you can ask a certified laboratory about PFAS testing using EPA Method 533 or 537.1 and its current price.