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Tan Oak Apts

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
325 people
Connections
5
Water source
Groundwater
Based in
Twin Lakes, WI
County
Kenosha
Owner
Private
Hardness
Very hard

The short answer

2 results are above the health goal. The worst: Arsenic, above the health goal. 1 health-based violation since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2010 to 2021.

Copper: EPA’s file records a utility’s copper only when it exceeds the action level. The last here was 12.2 ppm, for the period ending June 30, 1994. None since is on file, so it is not counted as a current finding.

Arsenic, fluoride, nitrate and chromium (total): Wisconsin’s own results, samples taken from Jan. 30, 2020 to May 8, 2024, with EPA’s 2012 to 2019 file for earlier years.

Above the health goal2

Arsenic

Comes from the source

Above the health goal

1.3ppb

Highest yearly average, 2021 to 2024

Averaged by year, the highest was 1.3 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. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 2.4 ppb, in 2012.

What handles it

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

Lead

Comes from pipes, often your own

Above the health goal

0.84ppb

90th percentile, 2021

In the latest period, 9 in 10 homes sampled were at or below 0.84 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

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.71ppm

Highest yearly average, 2021 to 2024

2024, one sample: 0.7 ppm

Averaged by year, the highest was 0.71 ppm, in 2021, below EPA’s legal limit of 4.0 ppm. In 2024, the latest year on file, its one sample was 0.7 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.84 ppm, in 2015.

What handles it

Nitrate

Comes from the source

Below EPA’s limits

0.035ppm

Highest sample; found in 1 of 2

2022: not found

The highest sample, in 2020, was 0.035 ppm, below EPA’s legal limit of 10 ppm. In 2022, the latest year on file, it wasn’t found in its one sample.

What handles it

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

  • NSF/ANSI 53

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

    For: Arsenic, Lead

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

  • NSF/ANSI 58

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

    For: Arsenic, Lead

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

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 reverse osmosis systems, ranked

The best water filters for lead, ranked

Hardness

Very hard, 250 mg/L (14.6 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 14.6 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. 4 monitoring or reporting violations not shown.

What this report can’t tell you

  • Everything else. Arsenic, fluoride, nitrate and chromium (total) results here are Wisconsin’s own from 2020 on, with EPA’s national file for 2012 to 2019. Tan Oak Apts’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. 30, 2020 to May 8, 2024.

Testing your own tap

Tan Oak Apts’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 Tan Oak Apts 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 WI2301080. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Kenosha County

All Wisconsin utilities

What to do next