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Adventist Health - St. Helena Hospital

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
617 people
Connections
196
Water source
Groundwater
Based in
St. Helena, CA
County
Napa
Owner
Private
Hardness
Soft
The ZIP code it serves

94574

The short answer

1 result is 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, nitrate, haloacetic acids (HAA5), total trihalomethanes (TTHM), fluoride, chromium (total) and uranium: California’s own results, samples taken from March 18, 2020 to June 23, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the health goal1

Arsenic

Comes from the source

Above the health goal

9.5ppb

Highest yearly average, 2020 to 2026

2026: not found

Averaged by year, the highest was 9.5 ppb, in 2023: below EPA’s legal limit of 10 ppb, but above its health goal of zero. Its highest single sample was 19 ppb. In 2026, the latest year on file, it wasn’t found in its one sample. EPA recorded no violation for arsenic at this utility since 2020. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 2.3 ppb, in 2014.

What handles it

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

Below EPA’s limits4

Nitrate

Comes from the source

Below EPA’s limits

3.9ppm

Highest sample; found in 58 of 112

2026 average: 0.25 ppm

The highest sample, in 2024, was 3.9 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, its 15 samples averaged 0.25 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 2.7 ppm, in 2012.

What handles it

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

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

13ppb

Highest yearly average, 2020 to 2026

2026: not found

Averaged by year, the highest was 13 ppb, in 2023, below EPA’s legal limit of 60 ppb. Its highest single sample was 26 ppb. In 2026, 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 8.8 ppb, in 2014.

What handles it

No certification claim covers this compound yet.

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

8.2ppb

Highest yearly average, 2020 to 2025

2025 average: 4.3 ppb

Averaged by year, the highest was 8.2 ppb, in 2022, below EPA’s legal limit of 80 ppb. Its highest single sample was 8.9 ppb. In 2025, the latest year on file, its two samples averaged 4.3 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 5.5 ppb, in 2017.

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

0.23ppm

Highest yearly average, 2020 to 2026

2026: not found

Averaged by year, the highest was 0.23 ppm, in 2020, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 0.36 ppm. In 2026, 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 0.28 ppm, in 2014.

What handles it

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

    Claim: Arsenic (Pentavalent)<=50 ppb Reduction

    For: Arsenic

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

  • NSF/ANSI 58

    Claim: Arsenic (Pentavalent)<=50 ppb Reduction

    For: Arsenic

    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

Soft, typically 42 mg/L (2.5 grains per gallon), across 9 sampling points, 2019 to 2026.

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 2.5 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, nitrate, haloacetic acids (HAA5), total trihalomethanes (TTHM), fluoride, chromium (total) and uranium results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Adventist Health - St. Helena Hospital’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 23, 2026.

Testing your own tap

Adventist Health - St. Helena Hospital’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 Adventist Health - St. Helena Hospital serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Sonoma County Public Health Laboratory

    Santa Rosa, CA · about 16 miles

    Certified for bacteria

    (707) 565-4711

  • Brelje and Race Laboratories, Inc.

    Santa Rosa, CA · about 17 miles

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

    (707) 544-8807

  • K Prime, LLC.

    Santa Rosa, CA · about 20 miles

    Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, PFAS

    (707) 527-7574

All 145 certified labs for California

Sources

PWSID CA2800625. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Napa County

All California utilities

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