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Oak Shores

What EPA’s and Iowa’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
55 people
Connections
22
Water source
Groundwater
Based in
Armstrong, IA
County
Emmet
Owner
Private
The ZIP code it serves

50514

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, fluoride, chromium (total) and nitrate: Iowa’s own results, samples taken from March 23, 2020 to March 30, 2026.

Above the health goal1

Arsenic

Comes from the source

Above the health goal

3.5ppb

Highest yearly average, 2020

Averaged by year, the highest was 3.5 ppb, in 2020: below EPA’s legal limit of 10 ppb, but above its health goal of zero. Its highest single sample was 5.0 ppb. That is the only year on file.

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 limits1

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.22ppm

Highest yearly average, 2020

Averaged by year, the highest was 0.22 ppm, in 2020, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 0.24 ppm. That is the only year on file.

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
  • Nitrate

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

Violations since 2016

No health-based violations on file with EPA since 2016. There is 1 monitoring or reporting violation: a sample missed, late or not reported.

What this report can’t tell you

  • Everything else. Arsenic, fluoride, chromium (total) and nitrate results here are Iowa’s own from 2020 on, with EPA’s national file for 2012 to 2019. Oak Shores’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; Iowa’s results run from March 23, 2020 to March 30, 2026.

Testing your own tap

Oak Shores’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 Iowa certifies.

The 2 labs Iowa certifies closest to the area Oak Shores serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • State Hygienic Laboratory - Lakeside

    Milford, IA · about 36 miles

    Certified for bacteria, nitrate, minerals and other inorganics

    (712) 337-3669

  • Foundation Analytical Laboratory

    Cherokee, IA · about 72 miles

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

    (712) 225-6989

State Hygienic Laboratory at the University of Iowa: Through the Grants-to-Counties program, private well owners in participating counties can have their water tested for total coliform bacteria and nitrate. Start with the county sanitarian at your county health department. No cost in a participating county. The Grants-to-Counties Program, State Hygienic Lab at the University of Iowa.

All 36 certified labs for Iowa

Sources

PWSID IA3203301. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Emmet County

All Iowa utilities

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