Skip to content
TapBuff
ZIP

Sinsinawa Dominicans Inc

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
213 people
Connections
78
Water source
Groundwater
Based in
Sinsinawa, WI
County
Grant
Owner
Private
Hardness
Very hard
The ZIP code it serves

53811

The short answer

2 results are above the health goal. The worst: Arsenic, above the health goal. No health-based violations on file since 2016.

What handles it

What was found

Arsenic, haloacetic acids (HAA5), fluoride, total trihalomethanes (TTHM), nitrate and chromium (total): Wisconsin’s own results, samples taken from March 25, 2020 to March 4, 2026, with EPA’s 2012 to 2019 file for earlier years.

Uranium: EPA’s compliance monitoring file, samples taken from April 23, 2018 to April 23, 2018. Newer results are in the utility’s annual water quality report.

Above the health goal2

Arsenic

Comes from the source

Above the health goal

0.9ppb

Highest yearly average, 2021 to 2024

Averaged by year, the highest was 0.9 ppb, in 2024: below EPA’s legal limit of 10 ppb, but above its health goal of zero. That was also the latest year on file.

What handles it

  • NSF/ANSI 58 look for “Arsenic (Pentavalent)<=50 ppb Reduction”
  • NSF/ANSI 53 look for “Arsenic (Pentavalent)<=50 ppb Reduction”

Uranium

Comes from the source

Above the health goal

0.26ppb

Highest yearly average, 2018

Averaged by year, the highest was 0.26 ppb, in 2018: below EPA’s legal limit of 30 ppb, but above its health goal of zero. That is the only year on file.

What handles it

Below EPA’s limits4

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

3.7ppb

Highest yearly average, 2021 to 2024

Averaged by year, the highest was 3.7 ppb, in 2024, below EPA’s legal limit of 60 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 1.0 ppb, in 2018.

What handles it

No certification claim covers this compound yet.

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.2ppm

Highest yearly average, 2021 to 2024

Averaged by year, the highest was 0.2 ppm, in 2024, below EPA’s legal limit of 4.0 ppm. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.15 ppm, in 2015.

What handles it

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

0.83ppb

Highest yearly average, 2021 to 2024

Averaged by year, the highest was 0.83 ppb, in 2024, 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 0.39 ppb, in 2015.

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

0.024ppm

Highest sample; found in 3 of 7

2026: not found

The highest sample, in 2022, was 0.024 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, it wasn’t found in its one sample. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 0.21 ppm, in 2013.

What handles it

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

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

    Claim: Arsenic (Pentavalent)<=50 ppb Reduction

    For: Arsenic

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

  • NSF/ANSI 58

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

    For: Arsenic, Uranium

    Other certifiers’ wording: Arsenic (Pentavalent)<=300 ppb Reduction; Arsenic (V) (300 ppb influent level)

At the tap, or for the whole house?

These come with the water itself, so a whole-house system certified for the same claims treats every tap and shower. A filter at the tap treats drinking water for much less. 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 reverse osmosis systems, ranked

Hardness

Very hard, 306 mg/L (17.9 grains per gallon), at its one sampling point, in 2018.

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 17.9 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. Arsenic, haloacetic acids (HAA5), fluoride, total trihalomethanes (TTHM), nitrate 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. Sinsinawa Dominicans Inc’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 March 25, 2020 to March 4, 2026; EPA’s compliance samples are from April 23, 2018 to April 23, 2018.

Testing your own tap

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

  • Lafayette County Health Department

    Darlington, WI · about 23 miles

    Certified for bacteria, nitrate

    (608) 776-4895

  • LV Labs WW, LLC

    Lancaster, WI · about 24 miles

    Certified for bacteria, nitrate

    (608) 723-4096

  • Iowa County

    Dodgeville, WI · about 36 miles

    Certified for bacteria

    (608) 930-9870

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 WI1220118. Rebuilt from EPA data on Oct. 18, 2026.

Also in Grant County

All Wisconsin utilities

What to do next