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Hilmar County Water District water quality report, rewritten

Serves
5,504
Connections
1,684
Water source
Groundwater
Based in
Hilmar, CA
County
Merced
Owner
Local government
The ZIP code it serves

95324

PWSID CA2410012 · EPA data

Read this first

Nothing in the federal data for this utility is above a health goal. That covers PFAS, lithium, lead and copper; it does not cover everything, so read what this report cannot tell you below.

14 health-based violations since 2016. Details are below.

What was found

Highlighted: above the health goal, or EPA’s health benchmark where there is no goal. Circled: above the legal limit in at least one sample, or the action level. Every scale puts that line at its middle.

None of the contaminants in the federal data below were found at or above EPA’s reporting levels.

Tested and not found

Below EPA’s minimum reporting level in every sample taken from June 3, 2025 to Dec. 3, 2025. Not found means not measured above that level, which is not the same as zero.

All 31 compounds tested and not found
  • 11Cl-PF3OUdS
  • 4:2 FTS
  • 6:2 FTS
  • 8:2 FTS
  • 9Cl-PF3ONS
  • ADONA
  • HFPO-DA (GenX)
  • Lead
  • Lithium
  • NEtFOSAA
  • NFDHA
  • NMeFOSAA
  • PFBA
  • PFBS
  • PFDA
  • PFDoA
  • PFEESA
  • PFHpA
  • PFHpS
  • PFHxA
  • PFHxS
  • PFMBA
  • PFMPA
  • PFNA
  • PFOA
  • PFOS
  • PFPeA
  • PFPeS
  • PFTA
  • PFTrDA
  • PFUnA

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleNov. 1, 2025 to Nov. 30, 202513.2 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleOct. 1, 2025 to Oct. 31, 202528 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJuly 1, 2025 to July 31, 202518.2 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleMarch 1, 2025 to March 31, 202511.3 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleFeb. 1, 2025 to Feb. 28, 202511.5 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJan. 1, 2025 to Jan. 31, 202510.6 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleDec. 1, 2024 to Dec. 31, 202416.2 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJuly 1, 2024 to July 31, 202411.7 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleMay 1, 2024 to May 31, 202411.6 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleApril 1, 2024 to April 30, 202431 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleMarch 1, 2024 to March 31, 202411.9 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleFeb. 1, 2024 to Feb. 29, 202415.9 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJan. 1, 2024 to Jan. 31, 202412.2 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJan. 1, 2023 to Dec. 31, 202314.7 MG/LArchived
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 1 monitoring or reporting violation not shown.

What this report cannot tell you

  • Levels of everything else. Federal bulk data carries results for PFAS, lithium, lead and copper, and violations for the rest. Nitrate, arsenic, disinfection byproducts and other levels are in Hilmar County Water District’s own annual report, which it must send you every year.
  • Your own plumbing. Lead results are the 90th percentile across homes the utility samples. Your home’s service line, solder and fixtures decide yours. A certified lab test is the only way to know.
  • Anything after the latest data. SDWIS data is from 2026 Q2; UCMR 5 samples are from June 3, 2025 to Dec. 3, 2025.

Other California utilities

All California utilities

Sources

What to do next

  • Nothing here is above a health goal

    In the federal data for this utility. That data does not cover everything, which is why the next step matters.

    Every contaminant TapBuff tracks

  • Get the utility’s own report

    Hilmar County Water District must send you a water quality report every year. It lists nitrate, arsenic and byproduct levels this page cannot.

    How to read it

  • Test your own tap for lead

    Your service line, solder and fixtures decide the lead at your faucet, not the utility’s average.

    Lead in your water: what to do

  • Decide if you want a filter at all

    A filter for taste or chlorine is a preference, not a need. The standards say what each kind can do.

    NSF/ANSI standards, decoded