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Winnebago Area Sanitary District

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
90 people
Connections
33
Water source
Surface water bought from another system
Based in
Winnebago, WI
County
Winnebago
Owner
Local government

The short answer

1 result is above the health goal. The worst: Lead, above the health goal. No health-based violations on file since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2024 to 2025.

Total trihalomethanes (TTHM) and haloacetic acids (HAA5): Wisconsin’s own results, samples taken from Sept. 4, 2024 to July 7, 2026.

Above the health goal1

Lead

Comes from pipes, often your own

Above the health goal

5.6ppb

90th percentile, 2025

In the latest period, 9 in 10 homes sampled were at or below 5.6 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 limits2

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

28.3ppb

Highest yearly average, 2024 to 2026

Averaged by year, the highest was 28.3 ppb, in 2026, below EPA’s legal limit of 80 ppb. That was also the latest year on file.

What handles it

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

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

10.2ppb

Highest yearly average, 2024 to 2026

2026, one sample: 6.4 ppb

Averaged by year, the highest was 10.2 ppb, in 2025, below EPA’s legal limit of 60 ppb. Its highest single sample was 12 ppb. In 2026, the latest year on file, its one sample was 6.4 ppb.

What handles it

No certification claim covers this compound yet.

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

Violations since 2016

No health-based violations on file with EPA since 2016.

What this report can’t tell you

  • Everything else. Total trihalomethanes (TTHM) and haloacetic acids (HAA5) results here are Wisconsin’s own from 2024 on, with EPA’s national file for 2012 to 2019. Winnebago Area Sanitary District’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 Sept. 4, 2024 to July 7, 2026.

Testing your own tap

Winnebago Area Sanitary District’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.

No lab Wisconsin certifies is within 75 miles of the area Winnebago Area Sanitary District serves on the state’s list. Some take samples by mail; the state’s page lists them all.

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 WI4712094. Rebuilt from EPA data on Oct. 18, 2026.

Also in Winnebago County

All Wisconsin utilities

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