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Norwalk 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
653 people
Connections
230
Water source
Groundwater
Based in
Norwalk, WI
County
Monroe
Owner
Local government
Hardness
Very hard
The ZIP code it serves

54648

The short answer

Nothing in EPA’s and Wisconsin’s records for this utility is above a health goal. That covers nitrate, arsenic and other regulated chemicals, plus lead and copper, not everything. No health-based violations on file since 2016.

What was found

Haloacetic acids (HAA5), total trihalomethanes (TTHM), fluoride, nitrate, arsenic and chromium (total): Wisconsin’s own results, samples taken from Feb. 25, 2020 to Aug. 5, 2026, with EPA’s 2012 to 2019 file for earlier years.

Below EPA’s limits4

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

12.2ppb

Highest yearly average, 2020 to 2026

2026, one sample: 6.3 ppb

Averaged by year, the highest was 12.2 ppb, in 2025, below EPA’s legal limit of 60 ppb. In 2026, the latest year on file, its one sample was 6.3 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 4.5 ppb, in 2014.

What handles it

No certification claim covers this compound yet.

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

7.6ppb

Highest yearly average, 2020 to 2026

Averaged by year, the highest was 7.6 ppb, in 2026, below EPA’s legal limit of 80 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 6.3 ppb, in 2015.

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

0.11ppm

Highest yearly average, 2020 to 2026

2026 average: 0.1 ppm

Averaged by year, the highest was 0.11 ppm, in 2023, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 0.16 ppm. In 2026, the latest year on file, its two samples averaged 0.1 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.09 ppm, in 2017.

What handles it

Nitrate

Comes from the source

Below EPA’s limits

0.018ppm

Highest sample; found in 6 of 14

2026 average: 0.002 ppm

The highest sample, in 2022, was 0.018 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, its two samples averaged 0.002 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 0.17 ppm, in 2015.

What handles it

  • NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
  • NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”
3 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Arsenic
  • Chromium (total)
  • Lead

Hardness

Very hard, typically 236 mg/L (13.8 grains per gallon), across 2 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 at 13.8 grains per gallon, 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.

What this report can’t tell you

  • Everything else. Haloacetic acids (HAA5), total trihalomethanes (TTHM), fluoride, nitrate, arsenic and chromium (total) results here are Wisconsin’s own from 2020 on, with EPA’s national file for 2012 to 2019. Norwalk 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 Feb. 25, 2020 to Aug. 5, 2026.

Testing your own tap

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

  • Monroe County Health Department

    Sparta, WI · about 13 miles

    Certified for bacteria

    (608) 269-8666

  • Leuther Laboratories LLC

    Coon Valley, WI · about 19 miles

    Certified for bacteria

    (608) 788-8180

  • A1 Advanced Pumping Service, Inc.

    West Salem, WI · about 22 miles

    Certified for bacteria, nitrate

    (608) 784-1888

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 WI6420296. Rebuilt from EPA data on Oct. 18, 2026.

Also in Monroe County

All Wisconsin utilities

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