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McNaughton Correctional Center

What EPA’s and Wisconsin’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
133 people
Connections
1
Water source
Groundwater
Based in
Lake Tomahawk, WI
County
Oneida
Owner
State government
Hardness
Varies by source
The ZIP code it serves

54539

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, nitrate and chromium (total): Wisconsin’s own results, samples taken from March 17, 2020 to Sept. 5, 2023, with EPA’s 2012 to 2019 file for earlier years.

Above the health goal1

Arsenic

Comes from the source

Above the health goal

1.4ppb

Highest yearly average, 2020 to 2023

Averaged by year, the highest was 1.4 ppb, in 2023: below EPA’s legal limit of 10 ppb, but above its health goal of zero. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.65 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”

Below EPA’s limits3

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.077ppm

Highest yearly average, 2020 to 2023

Averaged by year, the highest was 0.077 ppm, in 2023, below EPA’s legal limit of 4.0 ppm. That was also the latest year on file.

What handles it

Nitrate

Comes from the source

Below EPA’s limits

0.11ppm

Highest sample; found in 1 of 2

2021 average: 0.055 ppm

The highest sample, in 2021, was 0.11 ppm, below EPA’s legal limit of 10 ppm. That is the only year on file, and its two samples averaged 0.055 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 0.65 ppm, in 2018.

What handles it

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

Chromium (total)

Comes from the source

Below EPA’s limits

0.38ppb

Highest yearly average, 2020 to 2023

2023: not found

Averaged by year, the highest was 0.38 ppb, in 2020, below EPA’s legal limit of 100 ppb. Its highest single sample was 0.76 ppb. In 2023, the latest year on file, it wasn’t found in its one sample.

What handles it

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

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 to moderately hard depending on the source, 52 to 72 mg/L (3 to 4.2 grains per gallon), across 2 sampling points, in 2017.

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?Wisconsin water hardness, utility by utility

Violations since 2016

No health-based violations on file with EPA since 2016. There are 3 monitoring or reporting violations: a sample missed, late or not reported.

What this report can’t tell you

  • Everything else. Arsenic, fluoride, nitrate and chromium (total) results here are Wisconsin’s own from 2020 on, with EPA’s national file for 2012 to 2019. McNaughton Correctional Center’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; Wisconsin’s results run from March 17, 2020 to Sept. 5, 2023.

Testing your own tap

McNaughton Correctional Center’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 Wisconsin certifies.

The 3 labs Wisconsin certifies closest to the area McNaughton Correctional Center serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Oneida County Health Department

    Rhinelander, WI · about 15 miles

    Certified for bacteria

    (715) 369-6111

  • Eagle River Health Department Laboratory

    Eagle River, WI · about 16 miles

    Certified for bacteria

    (715) 479-3656

  • Northern Lake Service Inc. - Waukesha

    Waukesha, WI · about 37 miles

    Certified for bacteria, nitrate, minerals and other inorganics

    (715) 478-2777

Wisconsin State Laboratory of Hygiene: Well water test kits ordered by phone and shipped free; you pay to mail the sample back, and the lab bills you after testing. Tests run from bacteria alone to a homeowner package covering bacteria, nitrate, fluoride, metals, hardness, volatile organic compounds and atrazine. Bacteria is $35, nitrate $35, lead $38, and the homeowner package $450, as of July 1, 2026. Public Environmental and Water Testing Prices, Wisconsin State Laboratory of Hygiene.

All 156 certified labs for Wisconsin

Sources

PWSID WI7440115. Rebuilt from EPA data on Oct. 18, 2026.

Also in Oneida County

All Wisconsin utilities

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