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City of Plymouth

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
1,060 people
Connections
535
Water source
Surface water bought from another system
Based in
Plymouth, CA
County
Amador
Owner
Local government
The ZIP code it serves

95669

The short answer

1 result is above EPA’s legal limit. The worst: Total trihalomethanes (TTHM), above the legal limit. 2 health-based violations since 2016.

What handles it

What was found

Total trihalomethanes (TTHM) and haloacetic acids (HAA5): California’s own results, samples taken from Feb. 19, 2020 to May 19, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the legal limit1

Total trihalomethanes (TTHM)

Forms or is added in treatment

Above the legal limit

76.6ppb

Highest yearly average, 2020 to 2026

2026 average: 63.8 ppb

Averaged by year, the highest was 76.6 ppb, in 2021, below EPA’s legal limit of 80 ppb. Its highest single sample was 110 ppb. In 2026, the latest year on file, its four samples averaged 63.8 ppb. EPA judges this limit at each sampling point, and recorded a violation for total trihalomethanes (TTHM) at this utility in 2021. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 70.4 ppb, in 2015, and EPA recorded a violation in 2017.

What handles it

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

Below EPA’s limits1

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

50.6ppb

Highest yearly average, 2020 to 2026

2026 average: 41.3 ppb

Averaged by year, the highest was 50.6 ppb, in 2021, below EPA’s legal limit of 60 ppb. Its highest single sample was 79.1 ppb. In 2026, the latest year on file, its four samples averaged 41.3 ppb. EPA recorded no violation for haloacetic acids (HAA5) at this utility since 2020. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 46.5 ppb, in 2018.

What handles it

No certification claim covers this compound yet.

One compound tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Lead

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: Trihalomethanes (TTHM) Reduction

    For: Total trihalomethanes (TTHM)

    Other certifiers’ wording: VOC Reduction

  • NSF/ANSI 58

    Claim: Trihalomethanes (TTHM) Reduction

    For: Total trihalomethanes (TTHM)

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

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2021 to Dec. 31, 20210.081 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2017 to June 30, 20170.081 MG/LResolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 5 monitoring or reporting violations not shown.

What this report can’t tell you

  • Everything else. Total trihalomethanes (TTHM) and haloacetic acids (HAA5) results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. City of Plymouth’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 Feb. 19, 2020 to May 19, 2026.

Testing your own tap

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

  • 49er Water Laboratory

    Jackson, CA · about 11 miles

    Certified for bacteria, nitrate, minerals and other inorganics

    (530) 277-2770

  • Ceres Analytical Laboratory, Inc.

    El Dorado Hills, CA · about 14 miles

    Certified for organic chemicals

    (916) 932-5011

  • Onterris Laboratories, LLC

    El Dorado Hills, CA · about 14 miles

    Certified for organic chemicals, PFAS

    (916) 673-1520

All 145 certified labs for California

Sources

PWSID CA0310004. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Amador County

All California utilities

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