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Cal Am - Dunnigan

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
602 people
Connections
184
Water source
Groundwater
Based in
Sacramento, CA
County
Yolo
Owner
Private
Hardness
Very hard
The 2 ZIP codes it serves

95698, 95937

The short answer

2 results are above the health goal. The worst: Arsenic, above the health goal. No health-based violations on file since 2016.

What handles it

What was found

Arsenic, uranium, nitrate, chromium (total), fluoride, total trihalomethanes (TTHM) and haloacetic acids (HAA5): California’s own results, samples taken from Jan. 22, 2020 to June 9, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the health goal2

Arsenic

Comes from the source

Above the health goal

4.0ppb

Highest yearly average, 2020 to 2025

2025 average: 1.5 ppb

Averaged by year, the highest was 4.0 ppb, in 2022: below EPA’s legal limit of 10 ppb, but above its health goal of zero. Its highest single sample was 5.0 ppb. In 2025, the latest year on file, its two samples averaged 1.5 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 2.7 ppb, in 2018.

What handles it

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

Uranium

Comes from the source

Above the health goal

1.5ppb

Highest yearly average, 2021 to 2024

Averaged by year, the highest was 1.5 ppb, in 2024: below EPA’s legal limit of 30 ppb, but above its health goal of zero. That was also the latest year on file.

What handles it

Below EPA’s limits5

Nitrate

Comes from the source

Below EPA’s limits

5.1ppm

Highest sample; found in 184 of 192

2026 average: 3.6 ppm

The highest sample, in 2021, was 5.1 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, its 16 samples averaged 3.6 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 9.2 ppm, in 2017.

What handles it

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

Chromium (total)

Comes from the source

Below EPA’s limits

36.1ppb

Highest yearly average, 2020 to 2026

2026 average: 16.1 ppb

Averaged by year, the highest was 36.1 ppb, in 2023, below EPA’s legal limit of 100 ppb. Its highest single sample was 71 ppb. In 2026, the latest year on file, its 10 samples averaged 16.1 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 42.5 ppb, in 2017.

What handles it

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.39ppm

Highest yearly average, 2020 to 2025

2025 average: 0.32 ppm

Averaged by year, the highest was 0.39 ppm, in 2023, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 0.4 ppm. In 2025, the latest year on file, its two samples averaged 0.32 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.33 ppm, in 2019.

What handles it

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

3.8ppb

Highest yearly average, 2020 to 2025

2025 average: 1.9 ppb

Averaged by year, the highest was 3.8 ppb, in 2023, below EPA’s legal limit of 80 ppb. Its highest single sample was 4.3 ppb. In 2025, the latest year on file, its two samples averaged 1.9 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 1.3 ppb, in 2018.

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

0.55ppb

Highest yearly average, 2020 to 2025

2025: not found

Averaged by year, the highest was 0.55 ppb, in 2023, below EPA’s legal limit of 60 ppb. Its highest single sample was 1.1 ppb. In 2025, the latest year on file, it wasn’t found in any of its two samples.

What handles it

No certification claim covers this compound yet.

One compound tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • 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: Arsenic (Pentavalent)<=50 ppb Reduction

    For: Arsenic

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

  • NSF/ANSI 58

    Claims: Arsenic (Pentavalent)<=50 ppb Reduction, Uranium

    For: Arsenic, Uranium

    Other certifiers’ wording: 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

Hardness

Very hard, typically 285 mg/L (16.7 grains per gallon), across 4 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 at 16.7 grains per gallon, salt includedSoftener or salt-free conditioner?California water hardness, utility by utility

Violations since 2016

No health-based violations on file with EPA since 2016.

What this report can’t tell you

  • Everything else. Arsenic, uranium, nitrate, chromium (total), fluoride, total trihalomethanes (TTHM) and haloacetic acids (HAA5) results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Cal Am - Dunnigan’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. 22, 2020 to June 9, 2026.

Testing your own tap

Cal Am - Dunnigan’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 Cal Am - Dunnigan serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Eurofins Sacramento Service Center

    West Sacramento, CA · about 28 miles

    Certified for bacteria, nitrate, minerals and other inorganics

    (626) 386-1221

  • Eurofins Sacramento

    West Sacramento, CA · about 28 miles

    Certified for minerals and other inorganics, organic chemicals, PFAS

    (916) 373-5600

  • Bend Genetics LLC

    Sacramento, CA · about 35 miles

    (916) 550-1048

All 145 certified labs for California

Sources

PWSID CA5700712. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Yolo County

All California utilities

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