CheckPFAS

ZIP Code 95301

High Risk
High Risk PFAS Risk Level

PFAS above EPA limits detected

3 compounds exceed EPA Maximum Contaminant Levels in water serving this ZIP code. Standard pitcher filters like Brita do not remove PFAS. See filter recommendations below.

10
PFAS Detected
3
Above EPA Limits
1
Water System
1125%
Highest % of MCL

Compounds Exceeding EPA Limits

PFOS Exceeds EPA limit
0 ppt MCL: 4 ppt 1125% of limit
Detected: 45.00 ppt
PFOA Exceeds EPA limit
0 ppt MCL: 4 ppt 825% of limit
Detected: 33.00 ppt
PFHxS Exceeds EPA limit
0 ppt MCL: 10 ppt 590% of limit
Detected: 59.00 ppt

CITY OF ATWATER

CA2410001 High Risk
Water Type
Groundwater
PFAS Detected
10
Above MCL
3
State
California
Data Period
2023–2025

PFAS Test Results

CompoundDetectedvs. EPA LimitEPA LimitStatus
PFOS
Perfluorooctane sulfonic acid
45.00ppt
1125% of limit
4 ppt⚠ Exceeds MCL
PFOA
Perfluorooctanoic acid
33.00ppt
825% of limit
4 ppt⚠ Exceeds MCL
PFHxS
Perfluorohexane sulfonic acid
59.00ppt
590% of limit
10 ppt⚠ Exceeds MCL
PFPeA
Perfluoropentanoic acid
27.00pptNo federal limitUnregulated
PFHxA
Perfluorohexanoic acid
25.00pptNo federal limitUnregulated
6:2 FTS
6:2 Fluorotelomer sulfonic acid
13.00pptNo federal limitUnregulated
PFHpA
Perfluoroheptanoic acid
12.00pptNo federal limitUnregulated
PFBA
Perfluorobutanoic acid
11.00pptNo federal limitUnregulated
Show 2 more compounds detected at low levels
PFPeS8.20 pptNo federal limit
PFBSPerfluorobutane sulfonic acid7.80 pptNo federal limit

Data source: EPA Unregulated Contaminant Monitoring Rule, 5th cycle (UCMR 5) — January 2026 release.

UCMR 5 tested ~10,000 public water systems serving more than 25 people between 2023-2025 for 29 PFAS compounds.

Detection values represent the highest single-sample result measured at entry points to the distribution system.

View raw EPA data →