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Lake Morena'S Oak Shores 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
670 people
Connections
205
Water source
Groundwater
Based in
Campo, CA
County
San Diego
Owner
Private
Hardness
Varies by source
The ZIP code it serves

91906

The short answer

4 results are above the health goal. The worst: Nitrate, above the health goal. 1 health-based violation since 2016.

What handles it

What was found

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

Nitrate, uranium, arsenic, haloacetic acids (HAA5), total trihalomethanes (TTHM), fluoride and chromium (total): California’s own results, samples taken from Feb. 11, 2020 to June 2, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the health goal4

Nitrate

Comes from the source

Above the health goal

32ppm

Highest sample; found in 268 of 273

2026 average: 9.9 ppm

From 2020 to 2026, at least 25 samples were above EPA’s legal limit of 10 ppm, the highest 32 ppm in 2026. The next sample at the same point, within 30 days, kept the average above the limit for nine; 16 have no follow-up sample on file within 30 days. 10 ppm is also EPA’s health goal. That was also the latest year on file, and its 22 samples averaged 9.9 ppm. EPA recorded no violation for nitrate at this utility since 2020. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 40.5 ppm, in 2012, and EPA recorded violations in 2012, 2013, 2014 and 2015.

What handles it

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

Uranium

Comes from the source

Above the health goal

15.7ppb

Highest yearly average, 2020 to 2026

2026 average: 9.6 ppb

Averaged by year, the highest was 15.7 ppb, in 2021: below EPA’s legal limit of 30 ppb, but above its health goal of zero. Its highest single sample was 68.5 ppb. In 2026, the latest year on file, its 19 samples averaged 9.6 ppb. EPA recorded no violation for uranium at this utility since 2020. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 52.3 ppb, in 2012, and EPA recorded violations in 2012, 2013, 2014 and 2015.

What handles it

Lead

Comes from pipes, often your own

Above the health goal

6.9ppb

90th percentile, 2024 to 2026

In the latest period, 9 in 10 homes sampled were at or below 6.9 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

1.0ppb

Highest yearly average, 2022 to 2026

2026: not found

Averaged by year, the highest was 1.0 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 2026, 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 2.0 ppb, in 2014.

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

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

19ppb

Highest yearly average, 2020 to 2025

2025, one sample: 8.6 ppb

Averaged by year, the highest was 19 ppb, in 2022, below EPA’s legal limit of 60 ppb. In 2025, the latest year on file, its one sample was 8.6 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 8.6 ppb, in 2019.

What handles it

No certification claim covers this compound yet.

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

20ppb

Highest yearly average, 2020 to 2025

2025, one sample: 13 ppb

Averaged by year, the highest was 20 ppb, in 2023, below EPA’s legal limit of 80 ppb. In 2025, the latest year on file, its one sample was 13 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 14.6 ppb, in 2014.

What handles it

  • NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
  • NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.21ppm

Highest yearly average, 2022 to 2026

2026, one sample: 0.13 ppm

Averaged by year, the highest was 0.21 ppm, in 2022, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 0.26 ppm. In 2026, the latest year on file, its one sample was 0.13 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.2 ppm, in 2017.

What handles it

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

Hard to very hard depending on the source, 178 to 1380 mg/L (10.4 to 80.7 grains per gallon), across 5 sampling points, 2022 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. Nitrate, uranium, arsenic, haloacetic acids (HAA5), total trihalomethanes (TTHM), fluoride and chromium (total) results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Lake Morena'S Oak Shores 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 Feb. 11, 2020 to June 2, 2026.

Testing your own tap

Lake Morena'S Oak Shores 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 Morena'S Oak Shores MWC serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Metropolitan Solutions

    National City, CA · about 37 miles

    Certified for bacteria

    (619) 831-8100

  • Environmental Laboratory Network, Inc.

    San Diego, CA · about 39 miles

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

    (858) 266-1666

  • Analytical Environmental Lab, LLC

    San Diego, CA · about 41 miles

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

    (619) 871-8505

All 145 certified labs for California

Sources

PWSID CA3700923. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in San Diego County

All California utilities

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