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North Marin WD - Pt. Reyes

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
1,841 people
Connections
788
Water source
Groundwater
Based in
Novato, CA
County
Marin
Owner
Local government
Hardness
Varies by source
The ZIP code it serves

94956

The short answer

2 results are above the health goal. The worst: Arsenic, above the health goal. No health-based violations on file since 2016.

What handles it

What was found

Arsenic, total trihalomethanes (TTHM), haloacetic acids (HAA5), nitrate, fluoride and chromium (total): California’s own results, samples taken from Feb. 11, 2020 to May 12, 2026, with EPA’s 2012 to 2019 file for earlier years.

Uranium: EPA’s compliance monitoring file, samples taken from Dec. 11, 2012 to Feb. 5, 2015. Newer results are in the utility’s annual water quality report.

Above the health goal2

Arsenic

Comes from the source

Above the health goal

5.0ppb

Highest yearly average, 2020 to 2024

2024 average: 0.4 ppb

Averaged by year, the highest was 5.0 ppb, in 2021: below EPA’s legal limit of 10 ppb, but above its health goal of zero. Its highest single sample was 7.8 ppb. In 2024, the latest year on file, its five samples averaged 0.4 ppb.

What handles it

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

Uranium

Comes from the source

Above the health goal

0.022ppb

Highest yearly average, 2012 to 2015

2015: not found

Averaged by year, the highest was 0.022 ppb, in 2012: below EPA’s legal limit of 30 ppb, but above its health goal of zero. In 2015, the latest year on file, it wasn’t found in its one sample.

What handles it

Below EPA’s limits4

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

68ppb

Highest yearly average, 2020 to 2026

2026 average: 23.8 ppb

Averaged by year, the highest was 68 ppb, in 2022, below EPA’s legal limit of 80 ppb. Its highest single sample was 130 ppb. In 2026, the latest year on file, its four samples averaged 23.8 ppb. EPA recorded no violation for total trihalomethanes (TTHM) at this utility since 2020. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 58.8 ppb, in 2018.

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

20.5ppb

Highest yearly average, 2020 to 2026

2026 average: 15.7 ppb

Averaged by year, the highest was 20.5 ppb, in 2021, below EPA’s legal limit of 60 ppb. Its highest single sample was 40.7 ppb. In 2026, the latest year on file, its four samples averaged 15.7 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 18.1 ppb, in 2018.

What handles it

No certification claim covers this compound yet.

Nitrate

Comes from the source

Below EPA’s limits

0.62ppm

Highest sample; found in 1 of 13

2024: not found

The highest sample, in 2023, was 0.62 ppm, below EPA’s legal limit of 10 ppm. In 2024, the latest year on file, it wasn’t found in any of its five samples. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 1.8 ppm, in 2017.

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

0.075ppm

Highest yearly average, 2021 to 2024

2024 average: 0.06 ppm

Averaged by year, the highest was 0.075 ppm, in 2021, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 0.1 ppm. In 2024, the latest year on file, its five samples averaged 0.06 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.12 ppm, in 2015.

What handles it

2 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Chromium (total)
  • 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: Arsenic (Pentavalent)<=50 ppb Reduction

    For: Arsenic

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

  • NSF/ANSI 58

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

    For: Arsenic, Uranium

    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 very hard depending on the source, 100 to 365 mg/L (5.8 to 21.3 grains per gallon), across 5 sampling points, 2019 to 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

No health-based violations on file with EPA since 2016.

What this report can’t tell you

  • Everything else. Arsenic, total trihalomethanes (TTHM), haloacetic acids (HAA5), nitrate, fluoride and chromium (total) results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Uranium comes from EPA’s file alone, which ends in 2019. North Marin WD - Pt. Reyes’s own annual report, which it must send you every year, has newer results for those and 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. 11, 2020 to May 12, 2026; EPA’s compliance samples are from Dec. 11, 2012 to Feb. 5, 2015.

Testing your own tap

North Marin WD - Pt. Reyes’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 North Marin WD - Pt. Reyes serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Alpha Analytical Laboratories Inc. - North Bay

    Petaluma, CA · about 19 miles

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

    (707) 769-3128

  • Cel Analytical, Inc.

    San Francisco, CA · about 28 miles

    Certified for bacteria, minerals and other inorganics

    (415) 882-1690

  • Brelje and Race Laboratories, Inc.

    Santa Rosa, CA · about 29 miles

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

    (707) 544-8807

All 145 certified labs for California

Sources

PWSID CA2110006. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Marin County

All California utilities

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