Oshkosh Waterworks
EPA ID: WI4710457 · 63,000 people served · 6 ZIP codes
EPA compliance records for Oshkosh Waterworks show 7 unresolved violations — findings that remain open and are tracked at the federal level, covering a service territory of approximately 63,000 people.
Data: EPA SDWIS Last verified: 2026-04-02
Compliance Trajectory
Worsening · Risk tier: High · 95% chance of violation in next 12 months
Violations went from 1 (2021) to 4 (2024). The pattern suggests growing compliance challenges.
Service Area Map
Coverage area for Oshkosh Waterworks Source: EPA SDWIS service area boundaries.
Service area boundary — Grade D
Service Area Demographics
The Oshkosh Waterworks serves a community with a median household income of $80,181 and an estimated 81,939 residents across its service area. Approximately 62% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
🌊 Where Does Your Water Come From?
Oshkosh Waterworks's water is drawn from rivers, lakes, or reservoirs. Surface water sources are more exposed to agricultural runoff, stormwater, and upstream discharges, but they typically receive more intensive treatment before reaching your tap.
About 1% of homes in Winnebago County, Wisconsin rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Wastewater Proximity Note: This service area ranks in the 60th percentile nationally for proximity to wastewater discharge points. Surface water sources near wastewater outfalls may face additional treatment challenges.
Superfund Proximity Note: This service area ranks in the 60th percentile nationally for proximity to Superfund (NPL) sites.
Infrastructure Risk
Detected Contaminants
How Oshkosh Waterworks compares to EPA limits
What This Means For You
Stage 2 DBP Rule at 3 mg/L exceeds the EPA maximum of mg/L.
Lead and Copper Rule at 3 mg/L exceeds the EPA maximum of mg/L.
Contaminant 1011 at 1 mg/L exceeds the EPA maximum of mg/L.
Total Coliform at 1 presence exceeds the EPA maximum of presence.
Radium-226 at 1 pCi/L (combined Radium-226 & 228 ≤ 5 pCi/L) exceeds the EPA maximum of pCi/L (combined Radium-226 & 228 ≤ 5 pCi/L). Bone cancer and leukemia (known carcinogen). Consider ion exchange (water softener) filtration.
Radium-226 was detected in this water system. ion exchange (water softener) filtration can reduce exposure.
Find a certified water filter →Comparable Water Systems
Similar-sized systems in Wisconsin
Estimated Remediation Costs
Average estimated costs across ZIP codes served by this system
Based on national averages for common remediation projects. Actual costs vary by property. Only issues flagged by EPA, FEMA, or state data for each ZIP code are included.
System Overview
Oshkosh Waterworks (EPA ID: WI4710457) is a community water system in Wisconsin that serves approximately 63,000 people from surface water sources.
This system provides water to 6 ZIP codes across 2 communities.
Average Home Safety Score: D (54/100)
Based on water quality violations, lead levels, and radon risk across all ZIP codes served by this system.
Violation History
Recent Violations
| Date | Contaminant | Type | Status |
|---|---|---|---|
| July 2, 2025 | Stage 2 DBP Rule | Monitoring | Unresolved |
| January 1, 2025 | Stage 1 DBP Rule | Monitoring | Resolved |
| December 1, 2024 | Consumer Confidence Report Rule | Monitoring | Resolved |
| October 17, 2024 | Stage 2 DBP Rule | Health-based | Unresolved |
| October 17, 2024 | Lead and Copper Rule | Monitoring | Resolved |
| January 1, 2024 | Radium-226 | Monitoring | Unresolved |
| October 1, 2023 | Radium-228 | Monitoring | Unresolved |
| July 1, 2023 | Contaminant 1011 | Monitoring | Resolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Stage 2 DBP Rule | Treatment Failure | 3 | Yes |
| Lead and Copper Rule | Treatment Failure | 3 | No |
| Contaminant 1011 | Other Violation | 1 | No |
| Total Coliform | Microbiological | 1 | No |
| Radium-226 | Radionuclides | 1 | No |
| Radium-228 | Radionuclides | 1 | No |
| Stage 1 DBP Rule | Treatment Failure | 1 | No |
| Consumer Confidence Report Rule | Reporting Failure | 1 | No |
Lead & Copper
EPA Lead and Copper Rule sampling data for ZIP codes served by this system:
| ZIP Code | Lead Level | Exceeds Limit | Sample Date |
|---|---|---|---|
| 54901 | 0.011 mg/L | No | N/A |
| 54902 | 0.011 mg/L | No | N/A |
| 54903 | 0.011 mg/L | No | N/A |
| 54904 | 0.011 mg/L | No | N/A |
| 54906 | 0.011 mg/L | No | N/A |
Radon Risk in Service Area
Dominant radon zone for ZIP codes served by this system: Zone 2 (Moderate Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Need help with your water quality?
Typical cost: Water test: typically $20–$50 (DIY kit) · Professional inspection: $150–$400
Find the Right Water FilterFree tip: Let cold water run for 2 minutes before drinking — this helps flush lead from your pipes.
ZIP Codes Served
Coverage: 3 ZIP codes confirmed via EPA Community Water System Service Area Boundaries v3 plus 3 additional ZIPs inferred from SDWIS registry data. The EPA-confirmed set is the most reliable; SDWIS-inferred entries may be narrower than the real deployment area.
- 54901 — Oshkosh
- 54902 — Oshkosh
- 54903 — Oshkosh
- 54904 — Oshkosh
- 54906 — Oshkosh
- 54927 — Butte Des Morts
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Oshkosh Waterworks (WI4710457) on EPA.gov.
Frequently Asked Questions
Is Oshkosh Waterworks water safe to drink?
Oshkosh Waterworks has recorded 2 health-based violations in the past 5 years. While the system is required to treat water to meet federal standards, you may want to consider additional precautions such as a certified water filter.
How many people does Oshkosh Waterworks serve?
Oshkosh Waterworks serves approximately 63,000 people across 6 ZIP codes in Wisconsin.
Where does Oshkosh Waterworks get its water?
The primary water source is surface water.
Contact Your Water Utility
Public-record contact information for the water utility serving this system. Use these channels to request water quality reports, ask about service, or report issues directly.
Contact information from City of Oshkosh Water Utility Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility, does not act as its agent, and does not provide customer support for it. Contact details shown are public-record information from CCR filings. For service issues, contact the utility directly using the information above.
Water Source & Treatment
Where this water originates and how it's treated before reaching your tap.
Source: City of Oshkosh Water Utility Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility. Treatment and source data are sourced from the utility's published CCR filings.
The Wisconsin Department of Natural Resources (WDNR) has assessed the source of Oshkosh's drinking water and determined it to be of good quality normally, but regularly degraded as a result of various events (such as heavy precipitation and spring thawing).
Treatment regime
How this utility classifies its treatment process and what each reported treatment chemical does.
Treatment chemicals and what each one does
Chemical names are reported verbatim by the utility. Purpose categories are ZipCheckup annotations based on standard drinking-water treatment practice.
Watershed exposure sources reported
Land-use and natural conditions identified in the utility's source-water assessment as potential contamination sources upstream of treatment.
Treatment classification and chemical list sourced from City of Oshkosh Water Utility Consumer Confidence Report.
Treatment intensity is a ZipCheckup-derived classification based on the chemicals and processes the utility reports. Chemicals and contamination sources are taken verbatim from the utility's CCR filing. Routine federal monitoring and contaminant testing shown elsewhere on this page determine whether the water meets safety standards, not the treatment classification.
Federal UCMR5 PFAS Monitoring: Tested Clean
This water system was tested under the federal EPA Unregulated Contaminant Monitoring Rule (UCMR5). No PFAS compounds were detected.
Current MCL reflects the lowest state-enforceable limit (NYS 10 ppt for PFOA/PFOS, effective August 2020). The federal final MCL of 4 ppt for PFOA/PFOS (EPA April 2024 rule) is not enforceable until April 2029. Detections above 4 ppt but below 10 ppt are below current MCL but above the future federal limit.
Source: U.S. EPA UCMR5 (Unregulated Contaminant Monitoring Rule, 5th cycle) — per-system federal sampling, 2023–2025. EPA UCMR5 monitoring program →
PFAS Substances Detected in This System
This water system's Consumer Confidence Report disclosed the following PFAS compounds. Levels are from the utility's most recent reporting cycle.
In April 2024, EPA finalized the first National Primary Drinking Water Regulation for six PFAS. Public water systems have until 2029 to comply. EPA — PFAS regulation overview →
Source: Consumer Confidence Report disclosed by City of Oshkosh Water Utility.
ZipCheckup is not affiliated with this water utility. PFAS detection data is sourced from public Consumer Confidence Reports filed by the utility itself.
Lead Service Line Inventory
Service line breakdown reported under the federal Lead and Copper Rule Improvements (LCRI) inventory requirement:
Federal LCRI rule (effective October 2024) requires every public water system to inventory its service lines and complete lead-line replacement within 10 years.
Source: EPA SDWIS Federal Service Line Inventory (Phase 2) · Submitted 2026
ZipCheckup is not affiliated with the utility or state agency. Inventory figures render verbatim from the public LCRI submission cited above; ZipCheckup does not perform inspections or replacements.
Notable events and violations
This section summarizes events the utility chose to disclose in its most recent Consumer Confidence Report, plus any federal compliance violations the utility recorded against itself. Both lists are utility-authored — ZipCheckup does not audit, judge, or reorder them.
Federal compliance violations on record
These entries are taken verbatim from the utility's CCR violations section. EPA defines four broad violation categories: Maximum Contaminant Level (MCL), Treatment Technique (TT), Monitoring & Reporting (M&R), and Public Notification (PN).
-
reporting2024-10-17
Failed to develop an initial inventory for service line materials that meets federal requirements
Violations record from City of Oshkosh Water Utility Consumer Confidence Report.
ZipCheckup note: items above reflect what the utility published in its most recent CCR. Federal violation records are also tracked separately by the EPA Safe Drinking Water Information System (SDWIS) — the SDWIS record is the authoritative federal source for any specific regulatory action.
How Water Systems Appear in Rankings
Water systems are evaluated by violation history, contaminant detections, and service population. Larger systems with more service connections appear in more rankings.
Frequently Asked Questions
What You Can Do
Test your water
Home test kits can detect lead, bacteria, and other contaminants at your tap. Find the right filter →
Check your specific ZIP code
Water quality can vary within a system. View nearest ZIP report →
Contact your utility
Oshkosh Waterworks (EPA ID: WI4710457) — request the latest Consumer Confidence Report or ask about specific contaminants.