City of Dillon
EPA ID: MT0000201 · 4,300 people served · 1 ZIP code
Dating back across the full five-year EPA tracking window, City of Dillon encountered 11 violations, each subsequently remedied and closed — today the utility meets all federal drinking water requirements for the 4,300 residents in its service area and holds no open enforcement actions.
Data: EPA SDWIS Last verified: 2026-04-02
Service Area Map
Coverage area for City of Dillon Source: EPA SDWIS service area boundaries.
Service area boundary — Grade C
Service Area Demographics
The City of Dillon serves a community with a median household income of $57,967 and an estimated 8,223 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?
City of Dillon's water is pumped from underground aquifers. Groundwater is naturally filtered through rock and soil, but it can be vulnerable to PFAS contamination, nitrates from agriculture, and industrial chemicals that seep into the water table.
About 2% of homes in Beaverhead County, Montana rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Infrastructure Risk
Detected Contaminants
How City of Dillon compares to EPA limits
What This Means For You
Surface Water Treatment Rule at 8 mg/L exceeds the EPA maximum of mg/L.
Stage 1 DBP Rule at 2 mg/L exceeds the EPA maximum of mg/L.
Total Coliform at 1 presence exceeds the EPA maximum of presence.
Comparable Water Systems
Similar-sized systems in Montana
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 Dillon (EPA ID: MT0000201) is a community water system in Montana that serves approximately 4,300 people from groundwater sources.
This system serves ZIP code 59725 in Dillon.
Average Home Safety Score: C (65/100)
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 1, 2025 | Surface Water Treatment Rule | Monitoring | Resolved |
| October 1, 2024 | Stage 1 DBP Rule | Monitoring | Resolved |
| July 1, 2024 | Surface Water Treatment Rule | Monitoring | Resolved |
| July 1, 2023 | Surface Water Treatment Rule | Monitoring | Resolved |
| June 14, 2023 | Total Coliform | Monitoring | Resolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Surface Water Treatment Rule | Treatment Failure | 8 | No |
| Stage 1 DBP Rule | Treatment Failure | 2 | No |
| Total Coliform | Microbiological | 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 |
|---|---|---|---|
| 59725 | 0.003 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 MT or modeled from parcel and building-footprint data.
- 59725 — Dillon
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for City of Dillon (MT0000201) on EPA.gov.
Frequently Asked Questions
Is City of Dillon water safe to drink?
City of Dillon has only monitoring/reporting violations, which are procedural in nature. The system meets federal health-based standards.
How many people does City of Dillon serve?
City of Dillon serves approximately 4,300 people across 1 ZIP code in Montana.
Where does City of Dillon get its water?
The primary water source is groundwater.
Water Source & Treatment
Where this water originates and how it's treated before reaching your tap.
Source: DILLON CITY OF Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility. Treatment and source data are sourced from the utility's published CCR filings.
Treatment regime
How this utility classifies its treatment process and what each reported treatment chemical does.
Treatment classification and chemical list sourced from DILLON CITY OF 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 →
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.
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
City of Dillon (EPA ID: MT0000201) — request the latest Consumer Confidence Report or ask about specific contaminants.