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Capell Valley Estates

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
208 people
Connections
63
Water source
Surface water
Based in
Stockton, CA
County
Napa
Owner
Private
Hardness
Varies by source
The ZIP code it serves

94558

The short answer

1 result is above the limit’s level with no violation recorded, and 2 more are above the health goal. The worst: Total trihalomethanes (TTHM), above the limit’s level, no violation. 1 health-based violation since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2019 to 2028.

Total trihalomethanes (TTHM), arsenic, haloacetic acids (HAA5), nitrate, fluoride and chromium (total): California’s own results, samples taken from Feb. 3, 2020 to May 21, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the limit’s level, no violation recorded1

Total trihalomethanes (TTHM)

Forms or is added in treatment

Above the limit’s level, no violation

81.4ppb

Highest yearly average, 2020 to 2026

2026 average: 52.5 ppb

Averaged by year, the highest was 81.4 ppb, in 2021, above EPA’s legal limit of 80 ppb. Its highest single sample was 161 ppb. In 2026, the latest year on file, its four samples averaged 52.5 ppb. EPA judges this limit on running averages at each sampling point, and recorded no violation for total trihalomethanes (TTHM) 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 170 ppb, in 2013, and EPA recorded a violation in 2015.

What handles it

  • NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
  • NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”

Above the health goal2

Arsenic

Comes from the source

Above the health goal

2.7ppb

Highest yearly average, 2021 to 2026

2026 average: 1.7 ppb

Averaged by year, the highest was 2.7 ppb, in 2025: below EPA’s legal limit of 10 ppb, but above its health goal of zero. Its highest single sample was 3.0 ppb. In 2026, the latest year on file, its three samples averaged 1.7 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 3.4 ppb, in 2013.

What handles it

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

Lead

Comes from pipes, often your own

Above the health goal

3.0ppb

90th percentile, 2026 to 2028

In the latest period, 9 in 10 homes sampled were at or below 3.0 ppb, below EPA’s action level of 15 ppb. The action level drops to 10 ppb on Nov. 1, 2027. EPA’s health goal for lead is zero.

What handles it

Below EPA’s limits3

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

41.7ppb

Highest yearly average, 2020 to 2026

2026 average: 26.3 ppb

Averaged by year, the highest was 41.7 ppb, in 2022, below EPA’s legal limit of 60 ppb. Its highest single sample was 110 ppb. In 2026, the latest year on file, its four samples averaged 26.3 ppb. EPA recorded no violation for haloacetic acids (HAA5) at this utility since 2020. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 150 ppb, in 2013.

What handles it

No certification claim covers this compound yet.

Nitrate

Comes from the source

Below EPA’s limits

0.64ppm

Highest sample; found in 2 of 15

2026: not found

The highest sample, in 2025, was 0.64 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, it wasn’t found in any of its three samples.

What handles it

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

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.19ppm

Highest yearly average, 2020 to 2026

Averaged by year, the highest was 0.19 ppm, in 2026, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 0.28 ppm. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.13 ppm, in 2016.

What handles it

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

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: Trihalomethanes (TTHM) Reduction, Arsenic (Pentavalent)<=50 ppb Reduction, Lead Reduction

    For: Total trihalomethanes (TTHM), Arsenic, Lead

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

  • NSF/ANSI 58

    Claims: Trihalomethanes (TTHM) Reduction, Arsenic (Pentavalent)<=50 ppb Reduction, Lead Reduction

    For: Total trihalomethanes (TTHM), Arsenic, Lead

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

At the tap, or for the whole house?

Lead and copper usually come from pipes and fixtures inside or near your home. A whole-house system sits where water enters, so it cannot catch what your own plumbing adds after it. For those, the filter that counts is the one at the tap. 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 lead, ranked

Hardness

Moderately hard to very hard depending on the source, 120 to 208 mg/L (7 to 12.2 grains per gallon), across 3 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, 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. 2 monitoring or reporting violations not shown.

What this report can’t tell you

  • Everything else. Total trihalomethanes (TTHM), arsenic, haloacetic acids (HAA5), nitrate, fluoride and chromium (total) results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Capell Valley Estates’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 Feb. 3, 2020 to May 21, 2026.

Testing your own tap

Capell Valley Estates’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 Capell Valley Estates serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Caltest Analytical Laboratory

    Napa, CA · about 15 miles

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

    (707) 258-4000

  • Napa-Solano-Yolo-Marin Public Health Laboratory

    Fairfield, CA · about 17 miles

    Certified for bacteria

    (707) 784-4410

  • Brelje and Race Laboratories, Inc.

    Santa Rosa, CA · about 25 miles

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

    (707) 544-8807

All 145 certified labs for California

Sources

PWSID CA2800543. Rebuilt from EPA data on Oct. 18, 2026.

Also in Napa County

All California utilities

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