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Columbia Mobile Home Park

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
89 people
Connections
63
Water source
Groundwater
Based in
Newport Beach, CA
County
Tuolumne
Owner
Private
Hardness
Very hard
The ZIP code it serves

95370

The short answer

1 result is above EPA’s legal limit. The worst: Lead, above the action level. No health-based violations on file since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2011 to 2026.

Haloacetic acids (HAA5), chromium (total), fluoride, nitrate, arsenic and total trihalomethanes (TTHM): California’s own results, samples taken from Aug. 18, 2020 to Nov. 25, 2025, with EPA’s 2012 to 2019 file for earlier years.

Above the legal limit1

Lead

Comes from pipes, often your own

Above the action level

30ppb

90th percentile, 2024 to 2026

In the latest period, 9 in 10 homes sampled were at or below 30 ppb, above EPA’s action level of 15 ppb. The action level drops to 10 ppb on Nov. 1, 2027, and this result is at or above that. EPA’s health goal for lead is zero.

What handles it

Below EPA’s limits4

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

18ppb

Highest yearly average, 2020 to 2024

Averaged by year, the highest was 18 ppb, in 2024, below EPA’s legal limit of 60 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 3.4 ppb, in 2014.

What handles it

No certification claim covers this compound yet.

Chromium (total)

Comes from the source

Below EPA’s limits

18.4ppb

Highest yearly average, 2020 to 2023

2023, one sample: 15.1 ppb

Averaged by year, the highest was 18.4 ppb, in 2020, below EPA’s legal limit of 100 ppb. In 2023, the latest year on file, its one sample was 15.1 ppb.

What handles it

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.25ppm

Highest yearly average, 2020 to 2023

Averaged by year, the highest was 0.25 ppm, in 2023, below EPA’s legal limit of 4.0 ppm. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.11 ppm, in 2017.

What handles it

Nitrate

Comes from the source

Below EPA’s limits

0.59ppm

Highest sample; found in 4 of 6

2025: not found

The highest sample, in 2023, was 0.59 ppm, below EPA’s legal limit of 10 ppm. In 2025, the latest year on file, it wasn’t found in its one sample. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 1.1 ppm, in 2018.

What handles it

  • NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
  • NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”
2 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Arsenic
  • Total trihalomethanes (TTHM)

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.”

At the tap, or for the whole house?

Lead and copper usually come from pipes and fixtures inside or near your home. A whole-house system sits where water enters, so it cannot catch what your own plumbing adds after it. For those, the filter that counts is the one at the tap. 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 water filters for lead, ranked

Hardness

Very hard, 185 mg/L (10.8 grains per gallon), at its one sampling point, 2020 to 2023.

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 10.8 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 are 2 monitoring or reporting violations: a sample missed, late or not reported.

What this report can’t tell you

  • Everything else. Haloacetic acids (HAA5), chromium (total), fluoride, nitrate, arsenic and total trihalomethanes (TTHM) results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Columbia Mobile Home Park’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 Aug. 18, 2020 to Nov. 25, 2025.

Testing your own tap

Columbia Mobile Home Park’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 Columbia Mobile Home Park serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Precision Enviro-Tech

    Twain Harte, CA · about 8 miles

    Certified for bacteria

    (209) 477-8105

  • 49er Water Laboratory

    Jackson, CA · about 34 miles

    Certified for bacteria, nitrate, minerals and other inorganics

    (530) 277-2770

  • Aemtek, Inc.

    Modesto, CA · about 41 miles

    Certified for bacteria

    (510) 979-1979

All 145 certified labs for California

Sources

PWSID CA5500149. Rebuilt from EPA data on Oct. 18, 2026.

Also in Tuolumne County

All California utilities

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