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Monterey Park Tract CSD

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
186 people
Connections
51
Water source
Groundwater bought from another system
Based in
Ceres, CA
County
Stanislaus
Owner
Private
The ZIP code it serves

95307

The short answer

2 results are above EPA’s legal limit. The worst: Arsenic, above the legal limit. 4 health-based violations since 2016.

What handles it

What was found

Total trihalomethanes (TTHM) and haloacetic acids (HAA5): California’s own results, samples taken from Sept. 13, 2021 to Sept. 19, 2025.

Arsenic, nitrate, fluoride and chromium (total): EPA’s compliance monitoring file, samples taken from Jan. 26, 2012 to Aug. 1, 2016. Newer results are in the utility’s annual water quality report.

Above the legal limit2

Arsenic

Comes from the source

Above the legal limit

35.4ppb

Highest yearly average, 2012 to 2016

2016 average: 33.5 ppb

Averaged by year, the highest was 35.4 ppb, in 2013, about 3.5 times EPA’s legal limit of 10 ppb. Its highest single sample was 41 ppb. In 2016, the latest year on file, its four samples averaged 33.5 ppb, above the limit. EPA recorded violations for arsenic at this utility in 2012, 2013, 2014, 2015 and 2016.

What handles it

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

Nitrate

Comes from the source

Above the legal limit

17ppm

Highest sample; found in 22 of 22

2016 average: 14.1 ppm

From 2012 to 2016, 16 samples were above EPA’s legal limit of 10 ppm, the highest 17 ppm in 2016. The next sample at the same point, within 30 days, kept the average above the limit for two; 14 have no follow-up sample on file within 30 days. That was also the latest year on file, and its four samples averaged 14.1 ppm, above the limit. EPA recorded violations for nitrate at this utility in 2012, 2013, 2014, 2015 and 2016.

What handles it

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

Below EPA’s limits3

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

69.3ppb

Highest yearly average, 2021 to 2025

Averaged by year, the highest was 69.3 ppb, in 2025, below EPA’s legal limit of 80 ppb. That was also the latest year on file.

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

11ppb

Highest yearly average, 2021 to 2025

Averaged by year, the highest was 11 ppb, in 2025, below EPA’s legal limit of 60 ppb. That was also the latest year on file.

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, 2013 to 2016

2016: not found

Averaged by year, the highest was 0.2 ppm, in 2013, below EPA’s legal limit of 4.0 ppm. In 2016, the latest year on file, it wasn’t found in its one sample.

What handles it

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

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

    For: Arsenic, Nitrate

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

  • NSF/ANSI 58

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

    For: Arsenic, Nitrate

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

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

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

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The best reverse osmosis systems, ranked

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 SampleApril 1, 2016 to June 30, 201617 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2016 to June 30, 20160.031 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, 201614 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2016 to March 31, 20160.032 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. Total trihalomethanes (TTHM) and haloacetic acids (HAA5) results here are California’s own from 2021 on, with EPA’s national file for 2012 to 2019. Arsenic, nitrate, fluoride and chromium (total) come from EPA’s file alone, which ends in 2019. Monterey Park Tract CSD’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 Sept. 13, 2021 to Sept. 19, 2025; EPA’s compliance samples are from Jan. 26, 2012 to Aug. 1, 2016.

Testing your own tap

Monterey Park Tract CSD’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 Monterey Park Tract CSD serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Microbac Laboratories, Inc. - Turlock

    Turlock, CA · about 6 miles

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

    (707) 822-4649

  • Certified Laboratories - Turlock

    Turlock, CA · about 6 miles

    Certified for bacteria

    (209) 664-1100

  • Aemtek, Inc.

    Modesto, CA · about 11 miles

    Certified for bacteria

    (510) 979-1979

All 145 certified labs for California

Sources

PWSID CA5000389. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Stanislaus County

All California utilities

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