Community Water System · PWSID WI4710457

Oshkosh Waterworks

Serves 63,000 peopleSurface WaterOwner: Local GovernmentOshkosh, Wisconsin
1 open treatment violation.

Open for: Lead service line inventory. EPA counts treatment-technique violations as health-based: a required protective step was not done. It is not a measurement of contamination.

On record since 2018: 5 violations. 1 treatment lapse · 2 missed or late tests · 2 notices or reports. Most recent began 2025-07-02.

None of them is a measurement of contaminated water.

For this year's test results, ask the utility for its annual Consumer Confidence Report. Every community system must publish one.

0Over the limit
1Treatment lapse1 open
2Missed or late test
2Notice or report1 open

More violations on record than 87% of active water systems in Wisconsin. Small systems with no staff chemist often rack up missed-test violations; big utilities rarely do.

The record, year by year

2005201020152018 · Missed or late test: 120202023 · Missed or late test: 12024 · Treatment lapse: 12024 · Notice or report: 12025 · Notice or report: 12025
One square = one violation, by the year it began. Empty columns are years with nothing on EPA's record.
20% treatment lapse · 140% missed or late test · 240% notice or report · 2

Across Wisconsin, 54% of violations are missed or late tests and 5% are water over a limit.

Lead & copper at the tap

Utilities sample taps in homes most likely to have lead pipes, and report the 90th-percentile result: 9 in 10 homes sampled came in at or below this number. Above the red line (the action level) the utility must act. The action level is not a safe level; EPA's health goal for lead is zero. EPA's file does not date these results, so they are shown highest first.

Lead, 90th percentile 4 results on file · action level 15 ppb

12 ppb
11 ppb
7.5 ppb
6.1 ppb

Open now (2)

  1. 2025-07-02Lead service line inventoryRPTOpen
  2. 2024-10-17Lead service line inventoryTTOpen

Every violation on record

  1. 2025-07-02Lead service line inventoryRPTOpen
  2. 2024-10-17Lead service line inventoryTTOpen
  3. 2024-10-17Public NoticePN Violation for NPDWR ViolationBack in compliance
  4. 2023-07-01BromateMonitoring and Reporting (DBP)Back in compliance
  5. 2018-07-01BromateMonitoring and Reporting (DBP)Back in compliance

System details

Population served63,000
Service connections22,487
Water sourceSurface Water
System typeCommunity Water System
OwnerLocal Government
StatusActive
CityOshkosh
EPA ZIP on file54903

Areas served

  • Oshkosh, Winnebago County

Reading this record

Oshkosh Waterworks is a community water system that draws from surface water and serves about 63,000 people in Oshkosh, Wisconsin. Everything above comes from the EPA's Safe Drinking Water Information System (SDWIS), where states report every violation by every public water system.

Four kinds of violation. Only one is a measurement of the water: over the limit means a test came back above a legal maximum (an MCL). A treatment lapse means a required protective step was not done, such as disinfection, filtration, fixing a defect an inspector found, or filing a lead-pipe inventory. A missed or late test means a required test was skipped or never reported. That is the most common kind, and the most misread: it does not mean the water was bad, and it does not mean the water was fine. Notices and reports covers public notices and the annual Consumer Confidence Report.

Status. “Back in compliance” means the state recorded a return to compliance. “Period ended” means the violation's compliance period is over but no return to compliance was ever filed, which is common in older records. EPA's federal copy lags state records by months, so call the utility for anything current.