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Dexter Oaks Co - Op

What EPA’s and CDC’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
75 people
Connections
38
Water source
Groundwater
Based in
Dexter, OR
County
Lane
Owner
Private

The short answer

1 result is above EPA’s legal limit, and 1 more is above the health goal. The worst: Arsenic, above the legal limit. 17 health-based violations since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 1998 to 2022.

Arsenic and nitrate: Oregon’s yearly averages per water system, as CDC’s Environmental Public Health Tracking Network publishes them, 2020 to 2023, with EPA’s 2012 to 2019 file for earlier years.

Chromium (total), fluoride and uranium: EPA’s compliance monitoring file, samples taken from Dec. 2, 2016 to April 29, 2019. Newer results are in the utility’s annual water quality report.

Above the legal limit1

Arsenic

Comes from the source

Above the legal limit

27.5ppb

Highest yearly average, 2020 to 2023

2023 average: 3.0 ppb

Averaged by year, the highest was 27.5 ppb, in 2020, about 2.7 times EPA’s legal limit of 10 ppb. In 2023, the latest year on file, it averaged 3.0 ppb. EPA recorded violations for arsenic at this utility in 2020, 2021, 2022 and 2023. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 400 ppb, in 2016, and EPA recorded violations in 2016 and 2019.

What handles it

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

Above the health goal1

Lead

Comes from pipes, often your own

Above the health goal

9.9ppb

90th percentile, 2020 to 2022

In the latest period, 9 in 10 homes sampled were at or below 9.9 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

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

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

    For: Arsenic, Lead

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

  • NSF/ANSI 58

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

    For: 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

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Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2023 to March 31, 20230.013 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2022 to Dec. 31, 20220.018 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2022 to Sept. 30, 20220.023 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2022 to June 30, 20220.027 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2022 to March 31, 20220.022 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2021 to Dec. 31, 20210.021 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2021 to Sept. 30, 20210.019 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2021 to June 30, 20210.03 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2021 to March 31, 20210.034 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2020 to Dec. 31, 20200.027 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2020 to Sept. 30, 20200.028 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2020 to June 30, 20200.024 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2020 to March 31, 20200.021 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2019 to Dec. 31, 20190.024 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2019 to Sept. 30, 20190.016 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2019 to June 30, 20190.011 MG/LResolved
ArsenicA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJan. 1, 2016 to Dec. 31, 20160.4 MG/LResolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 9 monitoring or reporting violations not shown.

What this report can’t tell you

  • Everything else. Arsenic and nitrate results here are Oregon’s yearly averages as CDC publishes them, from 2020 on, with EPA’s national file for 2012 to 2019. Chromium (total), fluoride and uranium come from EPA’s file alone, which ends in 2019. Dexter Oaks Co - Op’s own annual report, which it must send you every year, has newer results for those and 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; CDC’s yearly averages for Oregon cover 2020 to 2023; EPA’s compliance samples are from Dec. 2, 2016 to April 29, 2019.

Testing your own tap

Dexter Oaks Co - Op’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 Oregon certifies.

No lab Oregon certifies is within 75 miles of the area Dexter Oaks Co - Op serves on the state’s list. Some take samples by mail; the state’s page lists them all.

Oregon State University Extension Well Water Program: Nitrate screening of well water at many of its groundwater education events. The screening is free. Water Testing Guidance for Private Wells, OSU Well Water Program.

All 91 certified labs for Oregon

Sources

PWSID OR4100998. Rebuilt from EPA data on Oct. 18, 2026.

Also in Lane County

All Oregon utilities

What to do next