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Marathon City 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
1,695 people
Connections
602
Water source
Groundwater
Based in
Marathon City, WI
County
Marathon
Owner
Local government
Hardness
Hard
The ZIP code it serves

54448

The short answer

1 result is above the health goal. The worst: Lead, above the health goal. 1 health-based violation since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2002 to 2023.

Total trihalomethanes (TTHM), nitrate, haloacetic acids (HAA5), fluoride, arsenic and chromium (total): Wisconsin’s own results, samples taken from Jan. 6, 2020 to Sept. 14, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the health goal1

Lead

Comes from pipes, often your own

Above the health goal

0.36ppb

90th percentile, 2023

In the latest period, 9 in 10 homes sampled were at or below 0.36 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 limits4

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

48.5ppb

Highest yearly average, 2020 to 2026

2026 average: 29.1 ppb

Averaged by year, the highest was 48.5 ppb, in 2025, below EPA’s legal limit of 80 ppb. Its highest single sample was 81.2 ppb. In 2026, the latest year on file, its six samples averaged 29.1 ppb. EPA recorded no violation for total trihalomethanes (TTHM) at this utility since 2020. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 87.6 ppb, in 2019.

What handles it

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

Nitrate

Comes from the source

Below EPA’s limits

3.9ppm

Highest sample; found in 2 of 2

2022, one sample: 3.2 ppm

The highest sample, in 2021, was 3.9 ppm, below EPA’s legal limit of 10 ppm. In 2022, the latest year on file, its one sample was 3.2 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 4.3 ppm, in 2013.

What handles it

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

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

10.7ppb

Highest yearly average, 2020 to 2026

2026 average: 6.7 ppb

Averaged by year, the highest was 10.7 ppb, in 2022, below EPA’s legal limit of 60 ppb. Its highest single sample was 17.2 ppb. In 2026, the latest year on file, its six samples averaged 6.7 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 18.7 ppb, in 2019.

What handles it

No certification claim covers this compound yet.

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.68ppm

Highest yearly average, 2020 to 2026

2026 average: 0.53 ppm

Averaged by year, the highest was 0.68 ppm, in 2020, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 0.95 ppm. In 2026, the latest year on file, its 19 samples averaged 0.53 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.54 ppm, in 2012.

What handles it

2 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Arsenic
  • 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.”

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

Hardness

Hard, 170 mg/L (9.9 grains per gallon), at its one sampling point, 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 at 9.9 grains per gallon, salt includedSoftener or salt-free conditioner?Wisconsin water hardness, utility by utility

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
Lead and Copper Rule RevisionsThe required inventory of lead service lines was not completed or submitted on time.EPA: LSL InventoryOct. 17, 2024—Resolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 7 monitoring or reporting violations not shown.

What this report can’t tell you

  • Everything else. Total trihalomethanes (TTHM), nitrate, haloacetic acids (HAA5), fluoride, arsenic and chromium (total) results here are Wisconsin’s own from 2020 on, with EPA’s national file for 2012 to 2019. Marathon City Waterworks’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 Jan. 6, 2020 to Sept. 14, 2026.

Testing your own tap

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

  • US Water, LLC

    Weston, WI · about 15 miles

    Certified for bacteria, nitrate, lead and copper, metals

    (715) 842-2215

  • Marathon County Public Health Laboratory

    Wausau, WI · about 16 miles

    Certified for bacteria, nitrate

    (715) 261-1908

  • Lincoln County Health Department

    Merrill, WI · about 20 miles

    Certified for bacteria, nitrate

    (715) 536-0307

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 WI7370151. Rebuilt from EPA data on Oct. 18, 2026.

Also in Marathon County

All Wisconsin utilities

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