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Chemeketa Park Mutual Water Company

What EPA’s and California’s records show in this utility’s water: nitrate, arsenic and other regulated chemicals; lead and copper; and violations since 2016, with the certification that handles each result.

Serves
346 people
Connections
153
Water source
Surface water
Based in
Santa Clara, CA
County
Santa Clara
Owner
Private
Hardness
Very hard
The ZIP code it serves

95033

The short answer

2 results are above EPA’s legal limit, and 1 more is above the health goal. The worst: Haloacetic acids (HAA5), above the legal limit. 3 health-based violations since 2016.

What handles it

What was found

Haloacetic acids (HAA5), total trihalomethanes (TTHM), arsenic, nitrate, fluoride, chromium (total) and uranium: California’s own results, samples taken from Jan. 22, 2020 to June 24, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the legal limit2

Haloacetic acids (HAA5)

Forms or is added in treatment

Above the legal limit

195ppb

Highest yearly average, 2020 to 2026

2026 average: 76.3 ppb

Averaged by year, the highest was 195 ppb, in 2025, about 3.3 times EPA’s legal limit of 60 ppb. In 2026, the latest year on file, its four samples averaged 76.3 ppb, above the limit. EPA recorded a violation for haloacetic acids (HAA5) at this utility in 2026. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 54 ppb, in 2019.

What handles it

No certification claim covers this compound yet.

Total trihalomethanes (TTHM)

Forms or is added in treatment

Above the legal limit

160ppb

Highest yearly average, 2020 to 2026

2026 average: 78.3 ppb

Averaged by year, the highest was 160 ppb, in 2025, about twice EPA’s legal limit of 80 ppb. In 2026, the latest year on file, its four samples averaged 78.3 ppb. EPA recorded a violation for total trihalomethanes (TTHM) at this utility in 2026. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 63 ppb, in 2015.

What handles it

  • NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
  • NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”

Above the health goal1

Arsenic

Comes from the source

Above the health goal

1.0ppb

Highest yearly average, 2020 to 2026

2026: not found

Averaged by year, the highest was 1.0 ppb, in 2021: below EPA’s legal limit of 10 ppb, but above its health goal of zero. Its highest single sample was 2.0 ppb. In 2026, the latest year on file, it wasn’t found in its one sample. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 1.1 ppb, in 2014.

What handles it

  • NSF/ANSI 58 look for “Arsenic (Pentavalent)<=50 ppb Reduction”
  • NSF/ANSI 53 look for “Arsenic (Pentavalent)<=50 ppb Reduction”

Below EPA’s limits3

Nitrate

Comes from the source

Below EPA’s limits

0.9ppm

Highest sample; found in 10 of 11

2026, one sample: 0.3 ppm

The highest sample, in 2022, was 0.9 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, its one sample was 0.3 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 1.5 ppm, in 2012.

What handles it

  • NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
  • NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.3ppm

Highest yearly average, 2020 to 2026

2026, one sample: 0.2 ppm

Averaged by year, the highest was 0.3 ppm, in 2020, below EPA’s legal limit of 4.0 ppm. In 2026, the latest year on file, its one sample was 0.2 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.33 ppm, in 2014.

What handles it

Chromium (total)

Comes from the source

Below EPA’s limits

3.1ppb

Highest yearly average, 2020 to 2026

2026: not found

Averaged by year, the highest was 3.1 ppb, in 2024, below EPA’s legal limit of 100 ppb. In 2026, the latest year on file, it wasn’t found in its one sample. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 2.0 ppb, in 2017.

What handles it

2 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Lead
  • Uranium

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: Trihalomethanes (TTHM) Reduction, Arsenic (Pentavalent)<=50 ppb Reduction

    For: Total trihalomethanes (TTHM), Arsenic

    Other certifiers’ wording: VOC Reduction; Arsenic (III) (50 ppb influent level)

  • NSF/ANSI 58

    Claims: Trihalomethanes (TTHM) Reduction, Arsenic (Pentavalent)<=50 ppb Reduction

    For: Total trihalomethanes (TTHM), Arsenic

    Other certifiers’ wording: Arsenic (Pentavalent)<=300 ppb Reduction; Arsenic (V) (300 ppb influent level)

At the tap, or for the whole house?

These come with the water itself, so a whole-house system certified for the same claims treats every tap and shower. A filter at the tap treats drinking water for much less. How whole-house systems compare.

Filters with those claims on a certifier’s listing

Disclosure: 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

Compare five-year costs

The best reverse osmosis systems, ranked

Hardness

Very hard, typically 204 mg/L (11.9 grains per gallon), across 2 sampling points, 2019 to 2026.

Hardness is calcium and magnesium. EPA sets no limit for it: it shows up as scale on fixtures and in water heaters, and as soap that won’t lather. USGS calls water above 60 mg/L moderately hard, above 120 hard and above 180 very hard.

Softeners compared at 11.9 grains per gallon, salt includedSoftener or salt-free conditioner?California water hardness, utility by utility

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
Total Haloacetic Acids (HAA5)The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2026 to June 30, 20260.089 MG/LArchived
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2026 to June 30, 20260.082 MG/LArchived
Total Haloacetic Acids (HAA5)The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2026 to March 31, 20260.074 MG/LArchived
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record.

What this report can’t tell you

  • Everything else. Haloacetic acids (HAA5), total trihalomethanes (TTHM), arsenic, nitrate, fluoride, chromium (total) and uranium results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Chemeketa Park Mutual Water Company’s own annual report, which it must send you every year, has the contaminants this page does not show.

  • 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.

  • What it means for your health. This page reports what the records show and EPA’s limits and goals; it is not medical advice. If you are worried about a health effect, talk to a doctor or your local health department.

  • Anything after the latest data. SDWIS data is from 2026 Q3; UCMR 5 didn’t sample this utility; California’s results run from Jan. 22, 2020 to June 24, 2026.

Testing your own tap

Chemeketa Park Mutual Water Company’s results are for the water it sends out. What your own service line, solder and fixtures add shows up only in a test of your tap, by a lab California certifies.

The 3 labs California certifies closest to the area Chemeketa Park Mutual Water Company serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Santa Cruz County - Health Services Agency - Environmental Health

    Santa Cruz, CA · about 12 miles

    Certified for bacteria

    (831) 454-4624

  • Torrent Laboratory, Inc

    Milpitas, CA · about 18 miles

    Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, organic chemicals, disinfection byproducts, PFAS

    (408) 263-5258

  • Bracewell Engineering, Inc.

    Morgan Hill, CA · about 19 miles

    Certified for bacteria, nitrate, minerals and other inorganics

    (669) 258-5821

All 145 certified labs for California

Sources

PWSID CA4300517. Rebuilt from EPA data on Oct. 18, 2026.

Also in Santa Clara County

All California utilities

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