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Blue Mountain Center

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
25 people
Connections
10
Water source
Groundwater
Based in
Tomales, CA
County
Marin
Owner
Private
Hardness
Moderately hard
The ZIP code it serves

94971

The short answer

Nothing in EPA’s and California’s records for this utility is above a health goal. That covers nitrate, arsenic and other regulated chemicals, plus lead and copper, not everything. No health-based violations on file since 2016.

What was found

Fluoride, arsenic, chromium (total) and nitrate: California’s own results, samples taken from April 6, 2020 to March 25, 2026.

Below EPA’s limits1

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.1ppm

Highest yearly average, 2021

Averaged by year, the highest was 0.1 ppm, in 2021, below EPA’s legal limit of 4.0 ppm. That is the only year on file.

What handles it

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

Hardness

Moderately hard, 77 mg/L (4.5 grains per gallon), at its one sampling point, 2021 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 at 4.5 grains per gallon, 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. There is 1 monitoring or reporting violation: a sample missed, late or not reported.

What this report can’t tell you

  • Everything else. Fluoride, arsenic, chromium (total) and nitrate results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Blue Mountain Center’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 April 6, 2020 to March 25, 2026.

Testing your own tap

Blue Mountain Center’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 Blue Mountain Center 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 15 miles

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

    (707) 769-3128

  • Brelje and Race Laboratories, Inc.

    Santa Rosa, CA · about 19 miles

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

    (707) 544-8807

  • Sonoma County Public Health Laboratory

    Santa Rosa, CA · about 20 miles

    Certified for bacteria

    (707) 565-4711

All 145 certified labs for California

Sources

PWSID CA2100549. Rebuilt from EPA data on Oct. 18, 2026.

Also in Marin County

All California utilities

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