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Is Okauchee Lake, WI tap water safe?

4 utilities serve Okauchee Lake, by EPA’s records. Here is what EPA’s and Wisconsin’s records show for each, against the legal limits and the stricter health goals.

Matched to your utility using EPA records.

The short answer

None of the 4 utilities serving Okauchee Lake has a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s and Wisconsin’s records.

Oconomowoc Waterworks, which serves the most people here, has 2 results above the health goal. The worst: Lead at 6.8 ppb, above the health goal. Health goals are stricter than legal limits and are not enforced.

The water from Oconomowoc Waterworks is very hard, typically 320 mg/L (18.7 grains per gallon). How Wisconsin’s water compares.

A town can be served by more than one utility, and some homes are on private wells. The name on your water bill tells you which is yours, and your ZIP code narrows it down. They are listed by how many people each serves in Okauchee Lake’s ZIP codes, from EPA’s estimates.

What handles it

Each of these is certified, on a certifier’s listing, for a result above a line in Oconomowoc Waterworks’s water, which serves the most people here. Another utility’s report names what handles its own results.

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Every claim, and more filters, in the full report

Water testing near Okauchee Lake

A utility tests the water it sends out. A test of your own tap shows what your pipes add, and on a private well it is the only test there is. It takes a lab Wisconsin certifies.

The 3 labs Wisconsin certifies closest to Okauchee Lake, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Waukesha Co Dept of Parks & Land Use – DEH

    Waukesha, WI · about 10 miles

    Certified for bacteria, nitrate

    (262) 896-8300

  • Watertown Department of Public Health Laboratory

    Watertown, WI · about 13 miles

    Certified for bacteria, nitrate

    (920) 262-8090

  • C & C Pumps LLC

    Hartford, WI · about 15 miles

    Certified for bacteria

    (262) 224-5576

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

ZIP codes in Okauchee Lake

Which ZIP codes are in Okauchee Lake: Census 2020 relationship files. Which utilities serve them, and how many people: EPA SDWIS and EPA’s service area map. Each utility’s results: EPA UCMR 5, EPA SDWIS, and EPA’s and the state’s compliance monitoring, as its report lists them. How they are measured: methodology. Certified labs: Wisconsin DNR and DATCP, certified and approved drinking water laboratories; distances from the Census 2020 ZIP code tabulation area gazetteer.

Near Okauchee Lake

Other towns in Waukesha County with a page of their own.

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