EPA data as of Oct 2026 · page updated 2026-10-30

Oconomowoc Waterworks

Oconomowoc Waterworks (EPA ID WI2680227) in Oconomowoc, WI supplies groundwater (wells) to about 15,805 people: no health-based violations since 2016, latest lead result 6.8 ppb, PFAS 2 detected.

Service area

EPA service-area boundary (state-supplied or EPA-modeled)
Water utility service area PFOA/PFOS ≥ 4 ppt Lead > 15 ppb 5+ violations Superfund site (active) proposed cleaned up Circles: other water systems flagged nearby; size = people served. Tap any symbol for details.

System facts

People served15,805
Connections1
Sourcegroundwater (wells)
WholesalerNo

Health-based violations

No health-based violations reported since 2016.

Lead

Jun 20236.8 ppb
Jul 20208.3 ppb
Jun 20177.1 ppb
Jun 20149 ppb
Jun 20118.6 ppb
Jan 20097 ppb
Jan 20089.9 ppb
Jan 20075.9 ppb

90th-percentile lead per sampling round (90% of the homes sampled were at or below this level). Black line: EPA’s 15 ppb action level; under the Lead and Copper Rule Improvements the action level becomes 10 ppb from 2027.

PFAS

CompoundHighest resultSamples with detectionEPA limit
PFBA5.4 ppt2 of 8—
PFBS4.6 ppt2 of 8—
HFPO-DA (GenX)not detected0 of 8—
PFPeAnot detected0 of 8—
PFHpAnot detected0 of 8—
PFOSnot detected0 of 84 ppt MCL
PFHxSnot detected0 of 8—
PFNAnot detected0 of 8—
PFOAnot detected0 of 84 ppt MCL
PFDAnot detected0 of 8—
PFHxAnot detected0 of 8—

EPA Fifth Unregulated Contaminant Monitoring Rule (UCMR 5), samples 2023–2025; ppt = parts per trillion (ng/L). The 4.0 ppt maximum contaminant levels for PFOA and PFOS were set by EPA in 2024; water systems have until the end of the decade to comply.

ZIP codes served

ZIP codes whose center lies in this system’s service area.

What this is — and isn’t. These are records your water utility and state reported to the EPA, and the EPA’s radon map for your county. They describe the system and the area, not the water from your own tap or the air in your home. For that, read your utility’s annual Consumer Confidence Report and test: lead and radon tests are inexpensive.

Questions

Has Oconomowoc Waterworks had drinking water violations?

No health-based violations reported since 2016.

What is the lead level in Oconomowoc Waterworks water?

The latest 90th-percentile lead result (Jun 2023) was 6.8 ppb. EPA’s action level is 15 ppb (10 ppb from 2027).

Does Oconomowoc Waterworks have PFAS in its water?

PFAS were detected, with PFOA and PFOS below 4.0 ppt (highest not detected).