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Green Valley CWD

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
1,275 people
Connections
499
Water source
Groundwater
Based in
Green Valley, CA
County
Los Angeles
Owner
Local government
Hardness
Varies by source
The ZIP code it serves

91390

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

Nitrate, uranium, total trihalomethanes (TTHM), fluoride, chromium (total), haloacetic acids (HAA5) and arsenic: California’s own results, samples taken from March 18, 2020 to June 10, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the health goal2

Nitrate

Comes from the source

Above the health goal

25.4ppm

Highest sample; found in 202 of 206

2026 average: 4.5 ppm

From 2023 to 2025, 14 samples were above EPA’s legal limit of 10 ppm, the highest 25.4 ppm in 2023. The next sample at the same point, within 30 days, kept the average above the limit for one; 13 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 14 samples averaged 4.5 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 8.5 ppm, in 2019.

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

1.2ppb

Highest yearly average, 2025

Averaged by year, the highest was 1.2 ppb, in 2025: below EPA’s legal limit of 30 ppb, but above its health goal of zero. Its highest single sample was 2.5 ppb. That is the only year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 1.1 ppb, in 2019.

What handles it

Below EPA’s limits4

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

17.5ppb

Highest yearly average, 2020 to 2025

2025 average: 4.9 ppb

Averaged by year, the highest was 17.5 ppb, in 2024, below EPA’s legal limit of 80 ppb. Its highest single sample was 29 ppb. In 2025, the latest year on file, its 10 samples averaged 4.9 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 24.6 ppb, in 2015.

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

0.66ppm

Highest yearly average, 2022 to 2025

Averaged by year, the highest was 0.66 ppm, in 2025, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 0.8 ppm. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.82 ppm, in 2016.

What handles it

Chromium (total)

Comes from the source

Below EPA’s limits

16ppb

Highest yearly average, 2022 to 2025

2025 average: 15.6 ppb

Averaged by year, the highest was 16 ppb, in 2022, below EPA’s legal limit of 100 ppb. Its highest single sample was 29 ppb. In 2025, the latest year on file, its nine samples averaged 15.6 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 1.9 ppb, in 2016.

What handles it

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

3.7ppb

Highest yearly average, 2020 to 2025

2025 average: 3.3 ppb

Averaged by year, the highest was 3.7 ppb, in 2020, below EPA’s legal limit of 60 ppb. Its highest single sample was 10 ppb. In 2025, the latest year on file, its three samples averaged 3.3 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 7.5 ppb, in 2016.

What handles it

No certification claim covers this compound yet.

2 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Arsenic
  • 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

    Claim: Nitrate/Nitrite (30 ppm challenge)

    For: Nitrate

  • NSF/ANSI 58

    Claims: Nitrate/Nitrite Reduction, Uranium

    For: Nitrate, Uranium

    Other certifiers’ wording: 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

Compare five-year costs

The best reverse osmosis systems, ranked

Hardness

Hard to very hard depending on the source, 150 to 304 mg/L (8.8 to 17.8 grains per gallon), across 10 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
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, total trihalomethanes (TTHM), fluoride, chromium (total), haloacetic acids (HAA5) and arsenic results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Green Valley CWD’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 March 18, 2020 to June 10, 2026.

Testing your own tap

Green Valley CWD’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 Green Valley CWD 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 CA1910244. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Los Angeles County

All California utilities

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