Is Oshkosh, WI tap water safe?
Supplied by Oshkosh Waterworks · serves 63,000 people (22,487 connections) · Surface water · EPA ID WI4710457
Data: U.S. EPA · How we read the data · How we check it
Most of Oshkosh gets its water from Oshkosh Waterworks. Parts of the city are served by a smaller system: Algoma Tn Sanitary District 1 (3,935 people). Your water bill names your system.
Summary
No federal limits exceeded in EPA data.
- PFAS
- Not detectedNone of 29 PFAS found above EPA's reporting limits in 4 samples (2023–2025).
- Lead
- Below action level6.1 ppb (parts per billion) at the 90th percentile: 9 in 10 homes sampled were at or below it. Action level 15 ppb, falling to 10 ppb in Nov 2027. Monitoring period ending Jun 2025. Your home's pipes can make yours higher.
- Violations
- None health-basedNo health-based violations since 2016.
- Built before 1986, or not sure what your service line is made of? Check your service line and test your tap. Utility data can't show your pipes.
- Tested your own tap? Compare your result with these numbers. Moving? Compare this system with another.
- Read Oshkosh Waterworks's annual water quality report (Consumer Confidence Report). It lists every regulated contaminant tested and is usually on the utility's website or mailed with your bill. EPA: how to find it.
PFAS (“forever chemicals”)
EPA UCMR 5: 1 entry point tested Feb 2023 to Nov 2023. "Average" is the highest entry-point average (non-detects counted as zero), the way EPA compares UCMR 5 results to the limits. ppt = parts per trillion. These results do not determine compliance.
| Contaminant | Highest average |
|---|---|
| PFOA Not detected Limit 4 ppt | – |
| PFOS Not detected Limit 4 ppt | – |
| PFHxS Not detected Limit 10 ppt | – |
| PFNA Not detected Limit 10 ppt | – |
| HFPO-DA (GenX) Not detected Limit 10 ppt | – |
| Hazard Index (a combined score for PFHxS, PFNA, GenX and PFBS, where above 1 is over the limit) Not detected Limit 1 | – |
| PFBS Not detected Guideline 2,000 ppt | – |
| PFBA Not detected Guideline 6,000 ppt | – |
| PFHxA Not detected Guideline 3,000 ppt | – |
29 PFAS tested, 0 detected at least once. "Not detected" means below EPA's reporting limit (about 2 to 20 ppt depending on the chemical), not proven zero. PFAS not listed were not detected. The limits for PFHxS, PFNA, GenX and the Hazard Index were proposed for rescission in May 2026. That proposal is not final. Systems have until 2029 to meet the limits.
Lithium
Not detected in 4 samples (reporting limit 9 ppb). About lithium.
Lead and copper
Latest 90th percentile: 6.1 ppb lead (Jan 2025 – Jun 2025). Below action level
Highest since 2016: 12 ppb (Sep 2017).
| Monitoring period | Lead (90th pct.) |
|---|---|
| Jan 2025 – Jun 2025 | 6.1 ppb |
| Jul 2024 – Dec 2024 | 7.5 ppb |
| Jul 2020 – Oct 2020 | 11 ppb |
Earlier results (9)
| Jun 2017 – Sep 2017 | 12 ppb |
| Jun 2014 – Sep 2014 | 9.3 ppb |
| Jun 2011 – Sep 2011 | 9.6 ppb |
| Jan 2008 – Dec 2008 | 7.5 ppb |
| Jan 2005 – Dec 2005 | 7.6 ppb |
| Jan 2002 – Jun 2002 | 8.3 ppb |
| Jul 1999 – Dec 1999 | 8.2 ppb |
| Jul 1998 – Dec 1998 | 6.6 ppb |
| Jul 1997 – Dec 1997 | 7.1 ppb |
Lead comes from pipes and fixtures, not the source water, so it varies home to home. The 90th percentile means 9 in 10 sampled homes were at or below it. More on lead.
Violations
Health-based violations mean a contaminant exceeded a limit or a required treatment step was missed. Monitoring and reporting violations mean required tests or reports were late or missing, so the water's quality during that time is unknown. The total includes every violation in EPA's records, most of them paperwork.
Earlier EPA testing (2013–2020)
| Contaminant | Highest | Guideline |
|---|---|---|
| Manganese | 1.32 ppb | 300 ppb |
| Chromium-6 | 0.06 ppb | – |
| Strontium | 0.085 ppm | 1.5 ppm |
| Vanadium | 1.9 ppb | 21 ppb |
Where it serves
Oshkosh
ZIP codes the system reported serving: 54901, 54902, 54904
Nearby utilities
- Appleton Waterworks Menasha · 15 mi
- Marshfield Utilities Marshfield · 21 mi · PFAS above limit
- Waupaca Waterworks Waupaca · 34 mi · PFAS above limit
- Kewaskum Waterworks Kewaskum · 39 mi · PFAS above limit
- Green Bay Waterworks Green Bay · 45 mi
- Hartford Waterworks Hartford · 49 mi · PFAS above limit
Questions
Is Oshkosh tap water safe to drink?
Most of Oshkosh gets its water from Oshkosh Waterworks. Oshkosh Waterworks has no health-based violations since 2016. EPA testing found no PFAS above the federal limits. Federal data can't tell you about your own pipes: lead comes from service lines and plumbing, so test your tap if your home was built before 1986. For the official word, read the utility's annual Consumer Confidence Report.
Does Oshkosh water have PFAS?
EPA tested Oshkosh Waterworks for 29 PFAS between Feb 2023 and Nov 2023 and none were detected above the reporting limits (about 2 to 20 ppt depending on the chemical).
What is the lead level in Oshkosh water?
The most recent 90th-percentile lead result for Oshkosh Waterworks is 6.1 ppb, for the period ending Jun 2025. The federal action level is 15 ppb, falling to 10 ppb in November 2027. The 90th percentile means 9 in 10 homes sampled were at or below this number. Individual homes can be higher.
Check these numbers yourself
Every figure on this page comes from public EPA records. You don't have to take our word for it:
- EPA's own report for WI4710457: violations, enforcement and inspections, straight from EPA.
- EPA UCMR 5 data: the PFAS and lithium results (search the file for PWSID WI4710457).
- EPA SDWIS download: the lead results, population and violation records we use.
- The utility's annual water quality report (Consumer Confidence Report): ask Oshkosh Waterworks, or see EPA's guide to finding it.
Found something that doesn't match? Tell us and we'll check it against EPA's records. How we check our data.
Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.