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North Trails Mutual Water Company

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
100 people
Connections
49
Water source
Groundwater
Based in
Agua Dulce, CA
County
Los Angeles
Owner
Private
Hardness
Varies by source
The ZIP code it serves

91390

The short answer

2 results are above EPA’s legal limit, 1 more is above the limit’s level with no violation recorded, and 1 more is above the health goal. The worst: Nitrate, above the legal limit. 16 health-based violations since 2016.

What handles it

What was found

Nitrate, arsenic, fluoride, uranium, chromium (total) and total trihalomethanes (TTHM): California’s own results, samples taken from Jan. 8, 2020 to June 10, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the legal limit2

Nitrate

Comes from the source

Above the legal limit

11.6ppm

Highest sample; found in 74 of 77

2026 average: 3.1 ppm

In 2024, two samples were above EPA’s legal limit of 10 ppm, the highest 11.6 ppm. The next sample at the same point, within 30 days, kept the average above the limit for one; one has no follow-up sample on file within 30 days. In 2026, the latest year on file, its six samples averaged 3.1 ppm. EPA recorded a violation for nitrate at this utility in 2024. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 5.0 ppm, in 2019.

What handles it

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

Arsenic

Comes from the source

Above the legal limit

11.3ppb

Highest yearly average, 2020 to 2026

2026 average: 6.5 ppb

Averaged by year, the highest was 11.3 ppb, in 2020, above EPA’s legal limit of 10 ppb. Its highest single sample was 13 ppb. In 2026, the latest year on file, its two samples averaged 6.5 ppb. EPA recorded violations for arsenic at this utility in 2020, 2021, 2022, 2023 and 2024. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 15 ppb, in 2015, and EPA recorded a violation in 2019.

What handles it

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

Above the limit’s level, no violation recorded1

Fluoride

Forms or is added in treatment

Above the limit’s level, no violation

4.6ppm

Highest yearly average, 2020 to 2026

2026 average: 3.2 ppm

Averaged by year, the highest was 4.6 ppm, in 2020, above EPA’s legal limit of 4.0 ppm. Its highest single sample was 5.1 ppm. In 2026, the latest year on file, its two samples averaged 3.2 ppm. EPA judges this limit on running averages at each sampling point, and recorded no violation for fluoride at this utility since 2020. Results like these with no violation often include water sampled before treatment or blending; the utility’s annual report says what reaches the tap. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 5.0 ppm, in 2015, and EPA recorded a violation in 2019.

What handles it

Above the health goal1

Uranium

Comes from the source

Above the health goal

9.1ppb

Highest yearly average, 2022 to 2025

Averaged by year, the highest was 9.1 ppb, in 2025: below EPA’s legal limit of 30 ppb, but above its health goal of zero. Its highest single sample was 17.6 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 15.5 ppb, in 2019.

What handles it

Below EPA’s limits1

Chromium (total)

Comes from the source

Below EPA’s limits

7.0ppb

Highest yearly average, 2021 to 2025

2025: not found

Averaged by year, the highest was 7.0 ppb, in 2024, below EPA’s legal limit of 100 ppb. Its highest single sample was 14 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 1.0 ppb, in 2015.

What handles it

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

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), Arsenic (Pentavalent)<=50 ppb Reduction, Fluoride

    For: Nitrate, Arsenic, Fluoride

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

  • NSF/ANSI 58

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

    For: Nitrate, Arsenic, Fluoride, Uranium

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

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

Compare five-year costs

The best reverse osmosis systems, ranked

The best water filters for fluoride, ranked

Hardness

Soft to hard depending on the source, 35 to 156 mg/L (2 to 9.1 grains per gallon), across 3 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, 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
NitrateThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJune 26, 2024 to June 25, 202511.6 MG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2024 to June 30, 202411 UG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2023 to June 30, 202311 UG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2022 to Dec. 31, 202211 UG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2022 to Sept. 30, 202211 UG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2022 to June 30, 202211 UG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2022 to March 31, 202211 UG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2021 to Dec. 31, 202112 UG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2020 to Sept. 30, 202013 UG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2020 to June 30, 202012 UG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2020 to March 31, 202012 UG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2019 to Dec. 31, 201912 UG/LArchived
FluorideThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2019 to Dec. 31, 20195.0 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2019 to Sept. 30, 201913 UG/LArchived
FluorideThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2019 to Sept. 30, 20195.1 MG/LResolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 4 monitoring or reporting violations not shown.

What this report can’t tell you

  • Everything else. Nitrate, arsenic, fluoride, uranium, chromium (total) and total trihalomethanes (TTHM) results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. North Trails Mutual Water Company’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. 8, 2020 to June 10, 2026.

Testing your own tap

North Trails Mutual Water Company’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 North Trails Mutual Water Company serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Pat-Chem Laboratories

    San Fernando, CA · about 18 miles

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

    (800) 400-5227

  • EMSL Analytical, Inc. (LA Testing)

    South Pasadena, CA · about 33 miles

    Certified for bacteria, asbestos

    (323) 254-9960

  • Positive Lab Service

    Los Angeles, CA · about 37 miles

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

    (213) 745-5312

All 145 certified labs for California

Sources

PWSID CA1907014. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Los Angeles County

All California utilities

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