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Lake of the Woods 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
875 people
Connections
394
Water source
Groundwater
Based in
Frazier Park, CA
County
Kern
Owner
Private
Hardness
Very hard
The ZIP code it serves

93225

The short answer

1 result is above EPA’s legal limit, and 3 more are above the health goal. The worst: Nitrate, above the legal limit. 12 health-based violations since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2006 to 2023.

Copper: EPA’s file records a utility’s copper only when it exceeds the action level. The last here was 1.8 ppm, for the period ending Dec. 31, 1996. None since is on file, so it is not counted as a current finding.

Nitrate, uranium, arsenic, fluoride, haloacetic acids (HAA5), total trihalomethanes (TTHM) and chromium (total): California’s own results, samples taken from Jan. 20, 2020 to June 3, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the legal limit1

Nitrate

Comes from the source

Above the legal limit

15ppm

Highest sample; found in 460 of 460

2026 average: 3.7 ppm

From 2020 to 2023, at least 25 samples were above EPA’s legal limit of 10 ppm, the highest 15 ppm in 2020. The next sample at the same point, within 30 days, kept the average above the limit for 19; two came back under and four have no follow-up sample on file within 30 days. In 2026, the latest year on file, its 26 samples averaged 3.7 ppm. EPA recorded a violation for nitrate at this utility in 2020. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 17 ppm, in 2016, and EPA recorded violations in 2016, 2017, 2018 and 2019.

What handles it

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

Above the health goal3

Uranium

Comes from the source

Above the health goal

24.6ppb

Highest yearly average, 2020 to 2025

2025 average: 15.8 ppb

Averaged by year, the highest was 24.6 ppb, in 2023: below EPA’s legal limit of 30 ppb, but above its health goal of zero. Its highest single sample was 26.8 ppb. In 2025, the latest year on file, its five samples averaged 15.8 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 21.6 ppb, in 2015.

What handles it

Lead

Comes from pipes, often your own

Above the health goal

1.2ppb

90th percentile, 2021 to 2023

In the latest period, 9 in 10 homes sampled were at or below 1.2 ppb, below EPA’s action level of 15 ppb. The action level drops to 10 ppb on Nov. 1, 2027. EPA’s health goal for lead is zero.

What handles it

Arsenic

Comes from the source

Above the health goal

0.6ppb

Highest yearly average, 2022 to 2025

2025 average: 0.4 ppb

Averaged by year, the highest was 0.6 ppb, in 2022: below EPA’s legal limit of 10 ppb, but above its health goal of zero. Its highest single sample was 3.0 ppb. In 2025, the latest year on file, its five samples averaged 0.4 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.56 ppb, in 2018.

What handles it

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

Below EPA’s limits3

Fluoride

Forms or is added in treatment

Below EPA’s limits

1.7ppm

Highest yearly average, 2020 to 2026

2026 average: 1.5 ppm

Averaged by year, the highest was 1.7 ppm, in 2022, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 2.9 ppm. In 2026, the latest year on file, its 16 samples averaged 1.5 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 2.2 ppm, in 2017.

What handles it

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

9.0ppb

Highest yearly average, 2020 to 2025

2025: not found

Averaged by year, the highest was 9.0 ppb, in 2022, below EPA’s legal limit of 60 ppb. 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 yearly average of 4.1 ppb, in 2017.

What handles it

No certification claim covers this compound yet.

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

9.9ppb

Highest yearly average, 2020 to 2025

2025, one sample: 9.0 ppb

Averaged by year, the highest was 9.9 ppb, in 2024, below EPA’s legal limit of 80 ppb. Its highest single sample was 14 ppb. In 2025, the latest year on file, its one sample was 9.0 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 12 ppb, in 2016.

What handles it

  • NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
  • NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”
One compound tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Chromium (total)

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

    Claims: Nitrate/Nitrite (30 ppm challenge), Lead Reduction, Arsenic (Pentavalent)<=50 ppb Reduction

    For: Nitrate, Lead, Arsenic

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

  • NSF/ANSI 58

    Claims: Nitrate/Nitrite Reduction, Uranium, Lead Reduction, Arsenic (Pentavalent)<=50 ppb Reduction

    For: Nitrate, Uranium, Lead, Arsenic

    Other certifiers’ wording: Nitrate; Arsenic (Pentavalent)<=300 ppb Reduction; Arsenic (V) (300 ppb influent level)

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 reverse osmosis systems, ranked

The best water filters for lead, ranked

Hardness

Very hard, typically 390 mg/L (22.8 grains per gallon), across 5 sampling points, 2019 to 2025.

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 22.8 grains per gallon, salt includedSoftener or salt-free conditioner?California water hardness, utility by utility

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJan. 1, 2020 to March 31, 202011 MG/LResolved
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleApril 1, 2019 to June 30, 201911 MG/LResolved
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJan. 1, 2019 to March 31, 201913 MG/LResolved
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleOct. 1, 2018 to Dec. 31, 201814 MG/LResolved
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJuly 1, 2018 to Sept. 30, 201813 MG/LResolved
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleApril 1, 2018 to June 30, 201811 MG/LResolved
NitrateThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2017 to June 30, 201712 MG/LResolved
NitrateThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2017 to March 31, 201714 MG/LResolved
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleOct. 1, 2016 to Dec. 31, 201617 MG/LResolved
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJuly 1, 2016 to Sept. 30, 201615 MG/LResolved
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleApril 1, 2016 to June 30, 201614 MG/LResolved
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJan. 1, 2016 to March 31, 201616 MG/LResolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 1 monitoring or reporting violation not shown.

What this report can’t tell you

  • Everything else. Nitrate, uranium, arsenic, fluoride, haloacetic acids (HAA5), total trihalomethanes (TTHM) and chromium (total) results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Lake of the Woods 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 Jan. 20, 2020 to June 3, 2026.

Testing your own tap

Lake of the Woods 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 Lake of the Woods MWC serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Fruit Growers Laboratory, Inc.

    Santa Paula, CA · about 30 miles

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

    (805) 392-2000

  • Capco Analytical Services

    Ventura, CA · about 37 miles

    Certified for bacteria, nitrate, metals, minerals and other inorganics

    (805) 644-1095

  • Ventura County Public Health Laboratory

    Oxnard, CA · about 39 miles

    Certified for bacteria

    (805) 981-5131

All 145 certified labs for California

Sources

PWSID CA1510023. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Kern County

All California utilities

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