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Yuima Municipal Water District

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
360 people
Connections
109
Water source
Surface water bought from another system
Based in
Pauma Valley, CA
County
San Diego
Owner
Local government
Hardness
Very hard
The ZIP code it serves

92061

The short answer

2 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 1997 to 2026.

Nitrate, total trihalomethanes (TTHM), haloacetic acids (HAA5), fluoride, arsenic, chromium (total) and uranium: California’s own results, samples taken from Jan. 14, 2020 to April 6, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the health goal2

Nitrate

Comes from the source

Above the health goal

18ppm

Highest sample; found in 87 of 87

2026 average: 5.5 ppm

From 2020 to 2022, 15 samples were above EPA’s legal limit of 10 ppm, the highest 18 ppm in 2022. The next sample at the same point, within 30 days, kept the average above the limit for eight; one came back under and six have no follow-up sample on file within 30 days. 10 ppm is also EPA’s health goal. In 2026, the latest year on file, its two samples averaged 5.5 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 27 ppm, in 2019, and EPA recorded a violation in 2018.

What handles it

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

Lead

Comes from pipes, often your own

Above the health goal

1.0ppb

90th percentile, 2024 to 2026

In the latest period, 9 in 10 homes sampled were at or below 1.0 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

Below EPA’s limits3

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

36ppb

Highest yearly average, 2020 to 2025

2025, one sample: 25 ppb

Averaged by year, the highest was 36 ppb, in 2023, below EPA’s legal limit of 80 ppb. In 2025, the latest year on file, its one sample was 25 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 22 ppb, in 2019.

What handles it

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

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

12ppb

Highest yearly average, 2020 to 2025

2025, one sample: 8.0 ppb

Averaged by year, the highest was 12 ppb, in 2023, below EPA’s legal limit of 60 ppb. In 2025, the latest year on file, its one sample was 8.0 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 23 ppb, in 2014.

What handles it

No certification claim covers this compound yet.

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.2ppm

Highest yearly average, 2020 to 2023

Averaged by year, the highest was 0.2 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 0.31 ppm, in 2016.

What handles it

3 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Arsenic
  • Chromium (total)
  • Uranium

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

    For: Nitrate, Lead

  • NSF/ANSI 58

    Claims: Nitrate/Nitrite Reduction, Lead Reduction

    For: Nitrate, Lead

    Other certifiers’ wording: Nitrate

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 340 mg/L (19.9 grains per gallon), across 3 sampling points, 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 19.9 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 SampleJuly 1, 2018 to July 31, 201812 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, total trihalomethanes (TTHM), haloacetic acids (HAA5), fluoride, arsenic, chromium (total) and uranium results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Yuima Municipal Water District’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. 14, 2020 to April 6, 2026.

Testing your own tap

Yuima Municipal Water District’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 Yuima Municipal Water District serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Applied Industrial Microbiology, Inc.

    Vista, CA · about 21 miles

    Certified for bacteria, nitrate

    (760) 295-0430

  • Alpha Analytical Laboratories, Inc. - San Diego

    Vista, CA · about 22 miles

    Certified for bacteria, nitrate, minerals and other inorganics

    (760) 536-3352

  • EMSL Analytical, Inc.

    San Diego, CA · about 35 miles

    Certified for bacteria

    (800) 220-3675

All 145 certified labs for California

Sources

PWSID CA3701408. Rebuilt from EPA data on Oct. 18, 2026.

Also in San Diego County

All California utilities

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