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Thorp Waterworks

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
1,636 people
Connections
774
Water source
Groundwater
Based in
Thorp, WI
County
Clark
Owner
Local government
Hardness
Varies by source
The ZIP code it serves

54771

The short answer

3 results are above the health goal. The worst: Lead, above the health goal. 2 health-based violations since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2011 to 2026.

Copper: EPA’s file records a utility’s copper only when it exceeds the action level. The last here was 2.0 ppm, for the period ending June 30, 1996. None since is on file, so it is not counted as a current finding.

Arsenic, nitrate, total trihalomethanes (TTHM), fluoride, haloacetic acids (HAA5) and chromium (total): Wisconsin’s own results, samples taken from Feb. 18, 2020 to Aug. 19, 2026, with EPA’s 2012 to 2019 file for earlier years.

Uranium: EPA’s compliance monitoring file, samples taken from Feb. 16, 2012 to April 16, 2019. Newer results are in the utility’s annual water quality report.

Above the health goal3

Lead

Comes from pipes, often your own

Above the health goal

11ppb

90th percentile, 2026

In the latest period, 9 in 10 homes sampled were at or below 11 ppb, below EPA’s action level of 15 ppb. The action level drops to 10 ppb on Nov. 1, 2027, and this result is at or above that. EPA’s health goal for lead is zero.

What handles it

Uranium

Comes from the source

Above the health goal

7.8ppb

Highest yearly average, 2012 to 2019

2019, one sample: 4.5 ppb

Averaged by year, the highest was 7.8 ppb, in 2012: below EPA’s legal limit of 30 ppb, but above its health goal of zero. Its highest single sample was 9.8 ppb. In 2019, the latest year on file, its one sample was 4.5 ppb.

What handles it

Arsenic

Comes from the source

Above the health goal

0.23ppb

Highest yearly average, 2020 to 2026

2026: not found

Averaged by year, the highest was 0.23 ppb, in 2020: below EPA’s legal limit of 10 ppb, but above its health goal of zero. Its highest single sample was 0.28 ppb. In 2026, the latest year on file, it wasn’t found in any of its four samples.

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 limits4

Nitrate

Comes from the source

Below EPA’s limits

9.3ppm

Highest sample; found in 32 of 32

2022 average: 5.6 ppm

The highest sample, in 2020, was 9.3 ppm, below EPA’s legal limit of 10 ppm. In 2022, the latest year on file, its seven samples averaged 5.6 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 8.6 ppm, in 2019.

What handles it

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

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

11.8ppb

Highest yearly average, 2020 to 2026

2026 average: 10.2 ppb

Averaged by year, the highest was 11.8 ppb, in 2022, below EPA’s legal limit of 80 ppb. Its highest single sample was 14.5 ppb. In 2026, the latest year on file, its two samples averaged 10.2 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 17.9 ppb, in 2016.

What handles it

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

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.24ppm

Highest yearly average, 2020 to 2026

2026 average: 0.11 ppm

Averaged by year, the highest was 0.24 ppm, in 2023, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 0.32 ppm. In 2026, the latest year on file, its four samples averaged 0.11 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.21 ppm, in 2017.

What handles it

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

3.2ppb

Highest yearly average, 2020 to 2026

2026 average: 2.0 ppb

Averaged by year, the highest was 3.2 ppb, in 2025, below EPA’s legal limit of 60 ppb. Its highest single sample was 3.5 ppb. In 2026, the latest year on file, its two samples averaged 2.0 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 3.7 ppb, in 2019.

What handles it

No certification claim covers this compound yet.

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

    For: Lead, Arsenic

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

  • NSF/ANSI 58

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

    For: Lead, Uranium, Arsenic

    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 water filters for lead, ranked

The best reverse osmosis systems, ranked

Hardness

Hard to very hard depending on the source, 130 to 230 mg/L (7.6 to 13.5 grains per gallon), across 5 sampling points, 2017 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?Wisconsin water hardness, utility by utility

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
Lead and Copper RuleRequired information about lead was not given to customers.EPA: Public EducationDec. 11, 2024—Resolved
Stage 1 Disinfectants and Disinfection Byproducts RuleTreatment was not run by a certified operator as required.EPA: Treatment Technique No Certif. OperatorNov. 2, 2022—Resolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 18 monitoring or reporting violations not shown.

What this report can’t tell you

  • Everything else. Arsenic, nitrate, total trihalomethanes (TTHM), fluoride, haloacetic acids (HAA5) and chromium (total) results here are Wisconsin’s own from 2020 on, with EPA’s national file for 2012 to 2019. Uranium comes from EPA’s file alone, which ends in 2019. Thorp Waterworks’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; Wisconsin’s results run from Feb. 18, 2020 to Aug. 19, 2026; EPA’s compliance samples are from Feb. 16, 2012 to April 16, 2019.

Testing your own tap

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

  • Chippewa County Department of Public Health

    Chippewa Falls, WI · about 28 miles

    Certified for bacteria, nitrate

    (715) 726-7900

  • Clark County Health Department

    Neillsville, WI · about 29 miles

    Certified for bacteria

    (715) 743-5105

  • Eau Claire City-County Health Department

    Eau Claire, WI · about 35 miles

    Certified for bacteria, nitrate, lead and copper, metals

    (715) 839-4718

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 WI6100337. Rebuilt from EPA data on Oct. 18, 2026.

Also in Clark County

All Wisconsin utilities

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