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Prunedale MWC

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
277 people
Connections
84
Water source
Groundwater
Based in
Salinas, CA
County
Monterey
Owner
Private
Hardness
Varies by source
The ZIP code it serves

93907

The short answer

1 result is above EPA’s legal limit. The worst: Arsenic, above the legal limit. 2 health-based violations since 2016.

What handles it

What was found

Arsenic, total trihalomethanes (TTHM), haloacetic acids (HAA5), fluoride, chromium (total) and nitrate: California’s own results, samples taken from Jan. 13, 2020 to June 2, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the legal limit1

Arsenic

Comes from the source

Above the legal limit

23.2ppb

Highest yearly average, 2020 to 2026

2026 average: 14.2 ppb

Averaged by year, the highest was 23.2 ppb, in 2021, about 2.3 times EPA’s legal limit of 10 ppb. Its highest single sample was 77.4 ppb. In 2026, the latest year on file, its 17 samples averaged 14.2 ppb, above the limit. EPA recorded a violation for arsenic at this utility in 2022. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 74.7 ppb, in 2016, and EPA recorded violations in 2013 and 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

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

11.5ppb

Highest yearly average, 2020 to 2023

2023, one sample: 11 ppb

Averaged by year, the highest was 11.5 ppb, in 2020, below EPA’s legal limit of 80 ppb. In 2023, the latest year on file, its one sample was 11 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 19 ppb, in 2017.

What handles it

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

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

3.0ppb

Highest yearly average, 2020 to 2023

2023: not found

Averaged by year, the highest was 3.0 ppb, in 2020, below EPA’s legal limit of 60 ppb. In 2023, 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 3.0 ppb, in 2017.

What handles it

No certification claim covers this compound yet.

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.077ppm

Highest yearly average, 2024

Averaged by year, the highest was 0.077 ppm, in 2024, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 0.13 ppm. That is the only year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.12 ppm, in 2015.

What handles it

3 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Chromium (total)
  • Lead
  • Nitrate

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

    Claim: Arsenic (Pentavalent)<=50 ppb Reduction

    For: Arsenic

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

  • NSF/ANSI 58

    Claim: Arsenic (Pentavalent)<=50 ppb Reduction

    For: 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

Moderately hard to hard depending on the source, 103 to 131 mg/L (6 to 7.7 grains per gallon), across 3 sampling points, in 2024.

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, salt includedSoftener or salt-free conditioner?California water hardness, utility by utility

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2022 to Dec. 31, 20220.02 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2022 to Sept. 30, 20220.011 MG/LResolved
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. Arsenic, total trihalomethanes (TTHM), haloacetic acids (HAA5), fluoride, chromium (total) and nitrate results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Prunedale MWC’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. 13, 2020 to June 2, 2026.

Testing your own tap

Prunedale MWC’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 Prunedale MWC serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Monterey County Consolidated Environmental Laboratory

    Salinas, CA · about 5 miles

    Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics

    (831) 755-4516

  • Monterey Bay Analytical Services, Inc.

    Monterey, CA · about 15 miles

    Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, radioactivity

    (831) 375-6227

  • CM Analytical, Inc.

    Gilroy, CA · about 17 miles

    Certified for bacteria

    (408) 848-3619

All 145 certified labs for California

Sources

PWSID CA2700702. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Monterey County

All California utilities

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