City of Mills
EPA ID: WY5600036 · 4,050 people served · 3 ZIP codes
The five-year EPA compliance file for City of Mills contains 6 violations, each documented and subsequently closed — the utility now operates in full compliance and continues to supply approximately 4,050 residents with water meeting current federal standards, including both health-based and monitoring requirements.
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 2 (2023) to 3 (2025). The pattern suggests growing compliance challenges.
Service Area Map
Coverage area for City of Mills Source: EPA SDWIS service area boundaries.
Service area boundary — Grade C
Service Area Demographics
The City of Mills serves a community with a median household income of $68,526 and an estimated 56,419 residents across its service area. Approximately 65% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
🌊 Where Does Your Water Come From?
City of Mills'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 Natrona County, Wyoming rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Superfund Proximity Note: This service area ranks in the 70th percentile nationally for proximity to Superfund (NPL) sites.
Infrastructure Risk
Detected Contaminants
How City of Mills compares to EPA limits
What This Means For You
Haloacetic Acids (HAA5) at 3 mg/L exceeds the EPA maximum of 0.06 mg/L. Cancer risk; reproductive & developmental effects. Consider granular activated carbon (GAC) filtration.
E. coli at 2 Zero tolerance (any positive sample triggers immediate action) exceeds the EPA maximum of Zero tolerance (any positive sample triggers immediate action). Severe GI illness; potentially fatal kidney failure in children. Consider UV disinfection (99.99%) filtration.
Consumer Confidence Report Rule at 1 mg/L exceeds the EPA maximum of mg/L.
Haloacetic Acids (HAA5) was detected in this water system. granular activated carbon (GAC) filtration can reduce exposure.
Find a certified water filter →Comparable Water Systems
Similar-sized systems in Wyoming
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
City of Mills, (EPA ID: WY5600036) is a community water system in Wyoming that serves approximately 4,050 people from surface water sources.
This system provides water to 3 ZIP codes across 2 communities.
Average Home Safety Score: C (67/100)
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 |
|---|---|---|---|
| January 1, 2025 | Haloacetic Acids (HAA5) | Health-based | Resolved |
| November 1, 2024 | E. coli | Monitoring | Resolved |
| November 1, 2024 | Consumer Confidence Report Rule | Monitoring | Resolved |
| October 1, 2024 | Haloacetic Acids (HAA5) | Health-based | Resolved |
| July 1, 2024 | Haloacetic Acids (HAA5) | Health-based | Resolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 3 | Yes |
| E. coli | Microbiological | 2 | No |
| Consumer Confidence Report Rule | Reporting Failure | 1 | No |
Health Risk Details
Haloacetic Acids (HAA5) (EPA limit: 0.06 mg/L)
Cancer risk; reproductive & developmental effects At-risk groups: pregnant women, infants, long-term consumers of chlorinated municipal water.
Removal methods: granular activated carbon (GAC), carbon block filter, reverse osmosis. Find the right filter →
Lead & Copper
EPA Lead and Copper Rule sampling data for ZIP codes served by this system:
| ZIP Code | Lead Level | Exceeds Limit | Sample Date |
|---|---|---|---|
| 82644 | 0.001 mg/L | No | N/A |
Radon Risk in Service Area
Dominant radon zone for ZIP codes served by this system: Zone 1 (High 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: Service area ZIP codes sourced from EPA Community Water System Service Area Boundaries v3 (March 2026 release). These ZIPs reflect the actual deployment footprint recorded by WY or modeled from parcel and building-footprint data.
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for City of Mills (WY5600036) on EPA.gov.
Frequently Asked Questions
Is City of Mills water safe to drink?
City of Mills has recorded 3 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 City of Mills serve?
City of Mills serves approximately 4,050 people across 3 ZIP codes in Wyoming.
Where does City of Mills get its water?
The primary water source is surface water.
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 →
Lead Service Line Inventory
Service line breakdown reported under the federal Lead and Copper Rule Improvements (LCRI) inventory requirement:
This system reports zero confirmed lead service lines in its inventory. Unknown-material counts may still warrant verification.
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.
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
City of Mills (EPA ID: WY5600036) — request the latest Consumer Confidence Report or ask about specific contaminants.