Lake Forest Mutual W.C.

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: 565 people
Connections: 220
Water source: Groundwater
Based in: Susanville, CA
County: Lassen
Owner: Private

The ZIP code it serves

96130

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

Nitrate and total trihalomethanes (TTHM): California’s own results, samples taken from May 13, 2020 to May 21, 2025, with EPA’s 2012 to 2019 file for earlier years.

Arsenic, chromium (total) and fluoride: EPA’s compliance monitoring file, samples taken from May 17, 2017 to May 17, 2017. Newer results are in the utility’s annual water quality report.

Below EPA’s limits1

Nitrate

Comes from the source

Below EPA’s limits

0.6ppm

Highest sample; found in 2 of 8

2025 average: 0.55 ppm

The highest sample, in 2025, was 0.6 ppm, below EPA’s legal limit of 10 ppm. That was also the latest year on file, and its two samples averaged 0.55 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 0.5 ppm, in 2019.

What handles it

NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”

5 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.

Arsenic
Chromium (total)
Fluoride
Lead
Total trihalomethanes (TTHM)

Violations since 2016

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

What this report can’t tell you

Everything else. Nitrate and total trihalomethanes (TTHM) results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Arsenic, chromium (total) and fluoride come from EPA’s file alone, which ends in 2019. Lake Forest Mutual W.C.’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 May 13, 2020 to May 21, 2025; EPA’s compliance samples are from May 17, 2017 to May 17, 2017.

Testing your own tap

Lake Forest Mutual W.C.’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.

No lab California certifies is within 75 miles of the area Lake Forest Mutual W.C. serves on the state’s list. Some take samples by mail; the state’s page lists them all.

All 145 certified labs for California