Skip to content
TapBuff
ZIP

Glen Martin 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
450 people
Connections
337
Water source
Groundwater
Based in
Angelus Oaks, CA
County
San Bernardino
Owner
Private
Hardness
Varies by source
The ZIP code it serves

92305

The short answer

1 result is above the health goal. The worst: Uranium, above the health goal. 1 health-based violation since 2016.

What handles it

What was found

Uranium, nitrate, fluoride, arsenic, chromium (total) and total trihalomethanes (TTHM): California’s own results, samples taken from March 6, 2020 to July 2, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the health goal1

Uranium

Comes from the source

Above the health goal

11.2ppb

Highest yearly average, 2020

Averaged by year, the highest was 11.2 ppb, in 2020: below EPA’s legal limit of 30 ppb, but above its health goal of zero. Its highest single sample was 11.3 ppb. That is the only year on file.

What handles it

Below EPA’s limits2

Nitrate

Comes from the source

Below EPA’s limits

2.9ppm

Highest sample; found in 16 of 24

2026 average: 0.98 ppm

The highest sample, in 2025, was 2.9 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, its three samples averaged 0.98 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 4.1 ppm, in 2014.

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

0.15ppm

Highest yearly average, 2020 to 2026

Averaged by year, the highest was 0.15 ppm, in 2026, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 0.16 ppm. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.1 ppm, in 2014.

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
  • 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?

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

None of the filters TapBuff has checked so far carry these claims. Search the certifier listings for the claim above.

Compare five-year costs

Hardness

Moderately hard to hard depending on the source, 100 to 130 mg/L (5.8 to 7.6 grains per gallon), across 3 sampling points, 2020 to 2026.

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
Lead and Copper Rule RevisionsThe required inventory of lead service lines was not completed or submitted on time.EPA: LSL InventoryOct. 17, 2024—Unaddressed
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 2 monitoring or reporting violations not shown.

What this report can’t tell you

  • Everything else. Uranium, nitrate, fluoride, arsenic, chromium (total) and total trihalomethanes (TTHM) results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Glen Martin 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 March 6, 2020 to July 2, 2026.

Testing your own tap

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

  • BSK Associates - San Bernardino Analytical Laboratory

    San Bernardino, CA · about 27 miles

    Certified for bacteria

    (559) 497-2888

  • Clinical Laboratory of San Bernardino, Inc.

    Grand Terrace, CA · about 30 miles

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

    (909) 825-7693

  • Babcock Laboratories, Inc.

    Riverside, CA · about 31 miles

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

    (951) 653-3351

All 145 certified labs for California

Sources

PWSID CA3610016. Rebuilt from EPA data on Oct. 18, 2026.

Also in San Bernardino County

All California utilities

What to do next