CheckPFAS

ZIP 95301 · California

Atwater, CA

High Risk

10 compounds detected

Above EPA drinking water limits

PFOS Exceeds limit
45.00 ppt (1125% of MCL)
→ 11.3× MCL
0 MCL: 4 ppt 45.0 ppt
PFOA Exceeds limit
33.00 ppt (825% of MCL)
→ 8.3× MCL
0 MCL: 4 ppt 33.0 ppt
PFHxS Exceeds limit
59.00 ppt (590% of MCL)
→ 5.9× MCL
0 MCL: 10 ppt 59.0 ppt
PFPeA no federal limit
27.00 ppt
0 40.5 ppt
PFHxA no federal limit
25.00 ppt
0 37.5 ppt
6:2 FTS no federal limit
13.00 ppt
0 19.5 ppt
PFHpA no federal limit
12.00 ppt
0 18 ppt
PFBA no federal limit
11.00 ppt
0 16.5 ppt
PFPeS no federal limit
8.20 ppt
0 12.3 ppt
PFBS no federal limit
7.80 ppt
0 11.7 ppt
Above EPA limit Below EPA limit No federal limit EPA MCL

Above EPA Limits

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.

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

Plain English

01What this means for you

One or more PFAS compounds were measured above the EPA's enforceable drinking water limit at a utility serving ZIP 95301. 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.

What to do next

02Three concrete steps

  1. 01

    Install a certified filter

    A reverse osmosis or NSF/ANSI 58-certified carbon block at your kitchen tap is the most reliable solution. Standard pitcher filters (Brita, PUR) don't remove PFAS unless explicitly certified for it. See certified filter picks →

  2. 02

    Read your utility's CCR

    Your water utility publishes an annual Consumer Confidence Report covering the previous year's water quality, including their PFAS treatment plan if any. More detailed than this site's summary. How to read a CCR →

  3. 03

    Reduce other exposure routes

    Water isn't the only input. Replace badly-scratched non-stick pans, skip microwave popcorn bags and greaseproof fast-food wrappers, and choose stainless or cast iron cookware. Full action plan on the FAQ →

Filter Recommendations

Find the right filter for your water
See our tested & reviewed PFAS-certified filters, ranked by CheckPFAS Score

CheckPFAS earns a small commission on filter purchases at no cost to you. Ranked by performance, not commission. Affiliate disclosure.

02CITY OF ATWATER

High Risk

PWSID · CA2410001

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 pptExceeds MCL
PFOA
Perfluorooctanoic acid
33.00ppt
825% of limit
4 pptExceeds MCL
PFHxS
Perfluorohexane sulfonic acid
59.00ppt
590% of limit
10 pptExceeds 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

Source & Methodology

About this data

Source
EPA UCMR 5
Data released
January 2026
Sampling period
January 2023 – December 2025
Systems tested
~10,000 public water systems
Water system (PWSID)
CA2410001
Detection threshold (MRL)
~1.5–2 ppt

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. "Not detected" means below the MRL, not literally zero.

View raw EPA UCMR 5 occurrence data →

Related

More resources for your area

  1. 01

    How to read your utility's CCR

    Decode your annual Consumer Confidence Report

  2. 02

    On a private well?

    PFAS testing guide for well owners — EPA rules don't apply

  3. 03

    All water systems in California

    Compare utilities statewide

  4. 04

    Which filter removes PFAS?

    Compare every method by removal rate & NSF certification

  5. 05

    PFAS health effects

    What the science shows, condition by condition

  6. 06

    PFAS compound guide

    Health effects & EPA limits for each compound