CheckPFAS

ZIP Code 95948

High Risk
High Risk PFAS Risk Level

PFAS above EPA limits detected

2 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.

6
PFAS Detected
2
Above EPA Limits
1
Water System
263%
Highest % of MCL

Compounds Exceeding EPA Limits

PFOS Exceeds EPA limit
0 ppt MCL: 4 ppt 263% of limit
Detected: 10.50 ppt
PFHxS Exceeds EPA limit
0 ppt MCL: 10 ppt 128% of limit
Detected: 12.80 ppt

What this means for you

One or more PFAS compounds were measured above the EPA's enforceable drinking water limit at a utility serving ZIP 95948. The EPA set these limits because long-term exposure at higher concentrations is associated with health effects including immune suppression, thyroid changes, and cancer risk increases. Standard pitcher filters (Brita, PUR) are not certified to remove PFAS. The most reliable at-home options are under-sink reverse osmosis systems or activated carbon block filters with an NSF/ANSI 58 certification specifically listing PFOA/PFOS reduction. Your water utility is required to bring levels into compliance by 2029 — filtering at the tap is the practical interim step if you'd like additional protection now.

CITY OF GRIDLEY

CA0410004 High Risk
Water Type
Groundwater
PFAS Detected
6
Above MCL
2
State
California
Data Period
2023–2025

PFAS Test Results

CompoundDetectedvs. EPA LimitEPA LimitStatus
PFOS
Perfluorooctane sulfonic acid
10.50ppt
263% of limit
4 ppt⚠ Exceeds MCL
PFHxS
Perfluorohexane sulfonic acid
12.80ppt
128% of limit
10 ppt⚠ Exceeds MCL
PFNA
Perfluorononanoic acid
9.90ppt
99% of limit
10 pptBelow limit
PFPeA
Perfluoropentanoic acid
6.50pptNo federal limitUnregulated
PFHxA
Perfluorohexanoic acid
5.30pptNo federal limitUnregulated
PFHpA
Perfluoroheptanoic acid
3.50pptNo federal limitUnregulated
About this data
Source
EPA UCMR 5 (Unregulated Contaminant Monitoring Rule, 5th cycle)
Data released
January 2026
Sampling period
January 2023 – December 2025
Systems tested
~10,000 public water systems serving > 25 people
Water system (PWSID)
CA0410004
Detection threshold (MRL)
~1.5–2 ppt — "Not detected" means below this floor, not zero

Values shown are the highest single-sample concentration measured at entry points to the distribution system. Results reflect water quality at the treatment plant — aging pipes, building plumbing, and on-site storage can affect what actually reaches your tap.