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Robin Way Water System

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
66 people
Connections
20
Water source
Groundwater
Based in
Fairfield, CA
County
Sonoma
Owner
Private
Hardness
Very hard
The ZIP code it serves

95407

The short answer

1 result is above EPA’s legal limit, and 1 more is above the health goal. The worst: Nitrate, above the legal limit. 5 health-based violations since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2006 to 2024.

Copper: EPA’s file records a utility’s copper only when it exceeds the action level. The last here was 3.1 ppm, for the period ending Dec. 31, 2009. None since is on file, so it is not counted as a current finding.

Nitrate, chromium (total), arsenic, fluoride, haloacetic acids (HAA5) and total trihalomethanes (TTHM): California’s own results, samples taken from Jan. 23, 2020 to May 11, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the legal limit1

Nitrate

Comes from the source

Above the legal limit

15ppm

Highest sample; found in 47 of 47

2026 average: 8.3 ppm

From 2022 to 2025, eight samples were above EPA’s legal limit of 10 ppm, the highest 15 ppm in 2023. Eight have no follow-up sample on file within 30 days. In 2026, the latest year on file, its three samples averaged 8.3 ppm. EPA recorded violations for nitrate at this utility in 2022 and 2023. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 14 ppm, in 2019, and EPA recorded a violation in 2019.

What handles it

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

Above the health goal1

Lead

Comes from pipes, often your own

Above the health goal

3.4ppb

90th percentile, 2022 to 2024

In the latest period, 9 in 10 homes sampled were at or below 3.4 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 limits1

Chromium (total)

Comes from the source

Below EPA’s limits

1.2ppb

Highest yearly average, 2020 to 2023

2023: not found

Averaged by year, the highest was 1.2 ppb, in 2020, below EPA’s legal limit of 100 ppb. In 2023, the latest year on file, it wasn’t found in its one sample.

What handles it

4 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Arsenic
  • Fluoride
  • Haloacetic acids (HAA5)
  • 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), Lead Reduction

    For: Nitrate, Lead

  • NSF/ANSI 58

    Claims: Nitrate/Nitrite Reduction, Lead Reduction

    For: Nitrate, Lead

    Other certifiers’ wording: Nitrate

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

Very hard, 255 mg/L (14.9 grains per gallon), at its one sampling point, 2020 to 2023.

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 14.9 grains per gallon, salt includedSoftener or salt-free conditioner?California water hardness, utility by utility

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleApril 1, 2023 to June 30, 202315 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJan. 1, 2023 to March 31, 202315 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJan. 1, 2022 to March 31, 202211 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJune 1, 2019 to June 30, 201914 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleMay 1, 2019 to May 31, 201912 MG/LArchived
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. Nitrate, chromium (total), arsenic, fluoride, haloacetic acids (HAA5) and total trihalomethanes (TTHM) results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Robin Way Water System’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. 23, 2020 to May 11, 2026.

Testing your own tap

Robin Way Water System’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 Robin Way Water System serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Brelje and Race Laboratories, Inc.

    Santa Rosa, CA · about 3 miles

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

    (707) 544-8807

  • Sonoma County Public Health Laboratory

    Santa Rosa, CA · about 5 miles

    Certified for bacteria

    (707) 565-4711

  • K Prime, LLC.

    Santa Rosa, CA · about 8 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 CA4900913. Rebuilt from EPA data on Oct. 18, 2026.

Also in Sonoma County

All California utilities

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