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City of Gilroy water quality report, rewritten

Serves
59,203
Connections
15,701
Water source
Groundwater
Based in
Gilroy, CA
County
Santa Clara
Owner
Local government
The 2 ZIP codes it serves

95020, 95021

PWSID CA43100042026 edition · EPA data

Read this first

  • PFOA (above the health goal) was found in six of 14 samples, highest 8.0 ppt. Above the 4.0 ppt legal limit in at least one sample. Compliance is judged on a running annual average, not one sample.
  • PFOS (above the health goal) was found in one of 14 samples, highest 5.8 ppt. Above the 4.0 ppt legal limit in at least one sample. Compliance is judged on a running annual average, not one sample.
  • Lithium (above EPA’s health benchmark) was found in four of 14 samples, highest 11 ppb. Above EPA’s health reference level of 10 ppb, a screening level rather than an enforceable limit.
  • Lead (above the health goal) In the latest period, 9 in 10 homes sampled were at or below 2.0 ppb, below the 15 ppb action level. The action level drops to 10 ppb on Nov. 1, 2027. EPA’s health goal for lead is zero.

1 health-based violation since 2016. Details are below.

What handles it

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.

PFOA (above the health goal)

Comes from the source

8.0 (above the legal limit in at least one sample)ppt

Highest of 14 samples; found in six

Above the 4.0 ppt legal limit in at least one sample. Compliance is judged on a running annual average, not one sample.

What handles it

  • NSF/ANSI 53Look for: PFOA ReductionSame claim, other certifiers’ wording: Total PFAS Reduction; Perfluorooctanoic Acid (PFOA)
  • NSF/ANSI 58Look for: Perfluorooctanoic Acid (PFOA)

NSF’s PFAS claims are tested to below 20 ppt. EPA’s limit is 4.0 ppt, and EPA says no certification yet shows a filter reaching its levels.

EPA UCMR 5, samples taken from Dec. 17, 2024 to June 25, 2025. Each blue tick is one sample where it was found.

PFOS (above the health goal)

Comes from the source

5.8 (above the legal limit in at least one sample)ppt

Highest of 14 samples; found in one

Above the 4.0 ppt legal limit in at least one sample. Compliance is judged on a running annual average, not one sample.

What handles it

  • NSF/ANSI 53Look for: PFOS ReductionSame claim, other certifiers’ wording: Total PFAS Reduction; Perfluorooctane Sulfonate (PFOS)
  • NSF/ANSI 58Look for: Perfluorooctane Sulfonate (PFOS)

NSF’s PFAS claims are tested to below 20 ppt. EPA’s limit is 4.0 ppt, and EPA says no certification yet shows a filter reaching its levels.

EPA UCMR 5, samples taken on Dec. 17, 2024. Each blue tick is one sample where it was found.

11ppb

Highest of 14 samples; found in four

Above EPA’s health reference level of 10 ppb, a screening level rather than an enforceable limit.

What handles it

No certification claim covers this compound yet.

EPA UCMR 5, samples taken on June 25, 2025. Each blue tick is one sample where it was found.

Lead (above the health goal)

Comes from pipes, often your own

2.0ppb

90th percentile, 2022 to 2024

In the latest period, 9 in 10 homes sampled were at or below 2.0 ppb, below the 15 ppb action level. The action level drops to 10 ppb on Nov. 1, 2027. EPA’s health goal for lead is zero.

What handles it

EPA SDWIS, lead and copper monitoring periods ending 2006 to 2024. The pointer marks the latest period; each blue tick is an earlier one.

PFHxS

Comes from the source

3.5ppt

Highest of 14 samples; found in one

Detected, below the legal limit and the health goal.

What handles it

  • NSF/ANSI 53Look for: Total PFAS ReductionSame claim, other certifiers’ wording: Perfluorohexane Sulfonic Acid (PFHxS)

NSF’s PFAS claims are tested to below 20 ppt. EPA’s limit is 10 ppt, and EPA says no certification yet shows a filter reaching its levels.

EPA UCMR 5, samples taken on Dec. 17, 2024. Each blue tick is one sample where it was found.

PFBS

Comes from the source

9.4ppt

Highest of 14 samples; found in five

Below EPA’s hazard index benchmark of 2,000 ppt. PFBS has no legal limit or health goal of its own.

What handles it

EPA UCMR 5, samples taken from Dec. 17, 2024 to June 25, 2025. Each blue tick is one sample where it was found.

Also found, with no federal limit

EPA measured these PFAS to learn how often they occur. None has a legal limit or a health goal yet.

CompoundHighest sampleFound inCertification claim
PFPeA7.8 ppt5 of 14None covers it
PFHxA7.0 ppt6 of 14None covers it
PFHpA3.6 ppt1 of 14NSF/ANSI 53: Total PFAS Reduction

Tested and not found

Below EPA’s minimum reporting level in every sample taken from Dec. 17, 2024 to July 23, 2025. Not found means not measured above that level, which is not the same as zero.

All 22 compounds tested and not found
  • 11Cl-PF3OUdS
  • 4:2 FTS
  • 6:2 FTS
  • 8:2 FTS
  • 9Cl-PF3ONS
  • ADONA
  • HFPO-DA (GenX)
  • NEtFOSAA
  • NFDHA
  • NMeFOSAA
  • PFBA
  • PFDA
  • PFDoA
  • PFEESA
  • PFHpS
  • PFMBA
  • PFMPA
  • PFNA
  • 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 SampleJune 1, 2022 to June 30, 202212 MG/LResolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record.

What handles it

A certification covers specific claims, not a whole standard. Look for these claims on the certifier’s listing, not the box. Wording varies a little: NSF writes “Lead Reduction,” WQA just “Lead.”

  • NSF/ANSI 53

    Claims: PFOA Reduction, PFOS Reduction, Lead Reduction

    For: PFOA, PFOS, Lead

  • NSF/ANSI 58

    Claims: Perfluorooctanoic Acid (PFOA), Perfluorooctane Sulfonate (PFOS), Lead Reduction

    For: PFOA, PFOS, Lead

At the tap, or for the whole house?

Lead and copper usually come from pipes and fixtures inside or near your home. A whole-house system sits where water enters, so it cannot catch what your own plumbing adds after it. For those, the filter that counts is the one at the tap. How whole-house systems compare.

Compare five-year costs

Filters with those claims on a certifier’s listing

TapBuff earns a commission if you buy through some links on this page. It does not change which standard or filter we name. As an Amazon Associate, TapBuff earns from qualifying purchases. How TapBuff makes money

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 City of Gilroy’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 Dec. 17, 2024 to July 23, 2025.

What to do next

  1. Read up on the 4 marked results

    What each one does to health, where it comes from, and the certification claim that addresses it.

    Start with PFOA

  2. Get the utility’s own report

    City of Gilroy must send you a water quality report every year. It lists nitrate, arsenic and byproduct levels this page cannot.

    How to read it

  3. 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

  4. Compare certified filters

    What the filters certified for these results cost over five years, cartridges included.

    Compare five-year costs

Other California utilities

All California utilities

Sources