Darby, MT: 1 Health Violation — 66/100 (2026)
1 ZIP code · 2 water systems · Updated 2026-06-03
Darby shows moderate tap water quality for MT — some areas carry documented EPA violations while others meet standards without issues.
How Darby Compares
Data: EPA SDWIS Last verified: 2026-06-03
Darby Water: The Quick Version
- Your city's water systems recorded 9 violations in the past 5 years.
- Average lead level: 0.005 mg/L.
- Homes built before 1986: 55% — older plumbing may contain lead solder.
- Estimated remediation: $2,700 per household.
- CDC health risk index: 12.93 — above typical levels.
Water Systems Serving Darby
Across Darby, MT, residential water comes from 2 primary utilities rather than a single consolidated provider. Each system operates independently — managing its own distribution infrastructure, rate schedules, and EPA compliance filings. Federal records track 2 water systems in the area, with these top providers accounting for the majority of residential connections.
Overview
We track water quality and home safety data for 1 ZIP code in Darby, Montana, covering 2 community water systems serving approximately 2,338 people.
1 of 1 ZIP code (100%) have recorded EPA violations. 1 health-based violation documented.
Home Safety Score
Average Home Safety Score for Darby: C (66/100)
The score combines three factors:
| Factor | What It Measures |
|---|---|
| Water Quality | EPA violations and compliance history |
| Lead Levels | 90th percentile lead concentration vs EPA action level |
| Radon Risk | EPA radon zone classification |
Water Sources
Darby water systems draw from: Groundwater.
Lead & Copper
- Average lead level (90th percentile): 0.0050 mg/L (EPA action level: 0.015 mg/L)
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 1 (High Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Top Contaminants
| Contaminant | Category | Violations | ZIPs Affected |
|---|---|---|---|
| Surface Water Treatment Rule | Treatment Technique | 8 | 1 |
| Consumer Confidence Report Rule | Reporting | 4 | 1 |
| Arsenic | Inorganic | 2 | 1 |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 2 | 1 |
| Stage 1 DBP Rule | Treatment Technique | 2 | 1 |
Areas with Most Violations
| ZIP Code | Safety Score | Violations | Health-Based | System |
|---|---|---|---|---|
| 59829 | C | 9 | 1 | Darby Town of |
All ZIP Codes in Darby
- 59829 [C] — 9 violations ⚠
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
Updated daily.
CDC Health Data for Darby
Source: CDC PLACES (County-level estimates). Water contamination can correlate with respiratory and chronic health conditions.
Compared to National Average
Vertical line = national average. ■ Above national · ■ Below national
Key Contaminants Detected in Darby
Based on EPA violation records. Check your ZIP code report for system-specific contaminant data.
How Old Is Darby's Housing Stock?
With 55% of homes built before 1986, lead solder in plumbing is a potential concern. The EPA banned lead solder in 1986, but many older homes retain original plumbing.
Source: U.S. Census Bureau American Community Survey (ACS).
Housing Age Profile
The median home in Darby was built in 1986 — a figure that places most of the city's residential stock in the era when lead solder was still standard in copper plumbing. Homes built before 1986 may have lead-soldered joints; those built before 1970 face the additional possibility of lead pipes in the service line itself.
Over half of homes in Darby were built before 1986, when lead solder was banned. Older plumbing may leach lead into drinking water, especially with corrosive water chemistry.
Source: U.S. Census Bureau ACS B25034.
Darby: Remediation Cost in Perspective
Because property values in Darby comfortably exceed estimated remediation costs, the equity impact here is proportionally small.
Remediation costs in Darby are relatively low compared to home values. The $1,750–$3,900 estimated range is a small fraction of median property value. Home values are 35% above the Montana average.
Protecting Children from Lead in Darby
Why children are most at risk: The CDC states there is no safe level of lead exposure for children. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.
Despite citywide averages serving as the standard public reference point, those aggregates cannot resolve what is happening at one specific faucet — and where 55% of Darby homes come from before the solder rule or where utility samples sit at or above the action mark, the gap between system data and faucet reality matters more than it does in lower-exposure communities. An in-home draw closes that gap, with certified filtration through retailer networks available where confirmed faucet results warrant additional measures.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Climate-Related Water Risk for Darby
6 FEMA flood insurance claims are on file for Darby, and 100% of local ZIP codes fall within federally designated flood zones — enough to put flood exposure on the planning radar, though short of the concentrated-risk threshold where treatment-system vulnerability becomes a primary consideration.
Darby has a moderate flood history with 6 FEMA claims averaging $5,127 per payout. 100% of ZIP codes fall within FEMA flood zones. Flood events can contaminate drinking water and overwhelm treatment systems.
How flooding affects water quality: Flood events can introduce sewage, agricultural runoff, and industrial chemicals into water supplies. Even after floodwaters recede, contamination can persist in wells and aging infrastructure. Flood damage can add significantly to the estimated <strong>$2,700</strong> remediation cost per household.
Residents in flood-prone areas should consider flood insurance even outside FEMA zones — over 25% of flood claims come from low-to-moderate risk areas. After any flood event, test your water before drinking.
Source: FEMA National Flood Insurance Program (NFIP) claims data, FEMA flood zone designations.
What You Can Do in Darby
- Test your water at home. City-level data shows averages — your tap may differ. NSF-certified test kits cost $20-40 and give results in days.
- Install a certified water filter. Filters rated for Surface Water Treatment Rule can reduce the most common contaminant found in Darby's water.
- Check your home's plumbing. With 55% of homes built before 1986, lead solder is a real possibility.
Deep Dive Reports
Detailed analysis for Darby, MT