Westport Bishops Bay Area

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: 80 people
Connections: 31
Water source: Groundwater bought from another system
Based in: Waunakee, WI
County: Dane
Owner: Local government

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

Total trihalomethanes (TTHM) and haloacetic acids (HAA5): Wisconsin’s own results, samples taken from Oct. 5, 2023 to July 10, 2025.

Below EPA’s limits2

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

10ppb

Highest yearly average, 2023 to 2025

2025 average: 4.4 ppb

Averaged by year, the highest was 10 ppb, in 2023, below EPA’s legal limit of 80 ppb. Its highest single sample was 11.9 ppb. In 2025, the latest year on file, its three samples averaged 4.4 ppb.

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

2.3ppb

Highest yearly average, 2023 to 2025

2025 average: 1.0 ppb

Averaged by year, the highest was 2.3 ppb, in 2023, below EPA’s legal limit of 60 ppb. Its highest single sample was 2.4 ppb. In 2025, the latest year on file, its three samples averaged 1.0 ppb.

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.

Lead

Violations since 2016

No health-based violations on file with EPA since 2016. There is 1 monitoring or reporting violation: a sample missed, late or not reported.

What this report can’t tell you

Everything else. Total trihalomethanes (TTHM) and haloacetic acids (HAA5) results here are Wisconsin’s own from 2023 on, with EPA’s national file for 2012 to 2019. Westport Bishops Bay Area’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 Oct. 5, 2023 to July 10, 2025.

Testing your own tap

Westport Bishops Bay Area’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 Westport Bishops Bay Area 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