Is Darby, MT Tap Water Safe to Drink?
Graded C — but Copper was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
60.2/100
waterverge.com Darby, MT — Water Quality Report
Darby's drinking water received a grade of C (60.2 out of 100), indicating fair water quality. The city's 2 water systems serve approximately 1,125 residents using groundwater.
Lead levels were measured at 0.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 246 violations on record, including 26 health-based violations. 24 remain unresolved.
What to know about Darby's water
Darby ranks #66 out of 115 cities in Montana for water quality, placing it below average in the state.
Darby relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff.
As a small community water system, Darby may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 10 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Darby, MT water safe to drink?
Darby's drinking water has significant quality concerns based on EPA testing data. With a grade of C (60.2/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 2 water systems serve approximately 1,125 residents using groundwater (wells).
Recent water quality updates for Darby
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Darby's water quality assessment. Grade: C (60.2/100).
Contaminants: Revised Total Coliform Rule.
1 health-based. Contaminants: Lead and Copper Rule.
Contaminants: Nitrate-Nitrite.
Federal disaster declaration (FEMA DR-4172). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-3253). Hurricane event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Darby's water supply.
Well within EPA limits.
Exceeds EPA action level. Copper can leach from household plumbing — flush taps for 30 seconds before drinking.
Violation history
Darby's water system has 246 total violations on record, including 26 health-based violations. 24 remain unresolved. 10 violations were issued in the last 5 years.
Flood & environmental risk
Ravalli County has experienced 2 federally declared disasters since 2005. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Bitterroot River Near Darby, Lake Como Near Darby.
Where does Darby's water come from?
Darby's drinking water comes from groundwater (wells), supplied by 2 water systems serving approximately 1,125 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Bitterroot River Near Darby (river), Lake Como Near Darby (lake).
What Darby residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Darby's water.
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Flood & disaster history
Ravalli County has experienced 2 federally declared disasters since 2005. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Darby's water supply, we recommend the following filter types.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 0.0 | 15 | ppb | Inorganic | Safe |
| Copper (90th percentile) CopperInorganic A metal that enters drinking water mainly through corrosion of copper plumbing. Small amounts are essential for health, but excess levels are harmful. Health EffectsGastrointestinal distress (nausea, vomiting, diarrhea) at short-term high levels; liver and kidney damage from long-term exposure. EPA Limit1.3 mg/L action level Common SourcesCorrosion of copper household plumbing, erosion of natural deposits. | 1.39 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level trend (90th percentile)
See how Darby compares by contaminant
Explore where Darby ranks among all Montana cities for specific contaminants.
Water source & infrastructure
Where Darby's water comes from
Darby's drinking water is drawn from underground aquifers through wells.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals.
Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds.
The system is operated by local government ownership and serves approximately 1,125 people through 2 water systems.
Water bodies near Darby
Darby is located near 2 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Darby
| System Name | PWSID | Population | Source |
|---|---|---|---|
| DARBY TOWN OF | MT0000195 | 850 | GW |
| TRAPPER CREEK JOB CORPS | MT0062207 | 275 | GW |
How Darby compares
Full Montana rankings →Darby's score of 60.2/100 is above the average of 45/100 among major Montana cities. It outscores 9 of 10 nearby cities.
Nearby cities
View Montana rankings →About Darby, MT
Wikipedia →Darby is a town in Ravalli County, Montana, United States. The population was 783 at the 2020 census. Darby is located near the southwestern border of Montana and Idaho, along the Continental Divide.
Learn more about your water
Guides and resources related to Darby's water quality findings.
Explore water quality across Ravalli
Frequently asked questions
Is Darby, MT tap water safe to drink?
Darby's water quality earned a grade of C (60.2/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #66 out of 115 cities tested in Montana.
What contaminants are in Darby's water?
Lead was measured at 0.0 ppb (90th percentile). 246 violations are on record.
How is Darby's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Darby?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Darby's water come from?
Darby's water is sourced from Groundwater. The city has 2 water systems serving approximately 1,125 residents.
What health violations has Darby's water system had?
Darby has 26 health-based violations on record. The most recent violation was recorded in December 2024. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 24 violations remain unresolved.
Is Darby's groundwater at risk of contamination?
Darby uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 246 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Darby's water compare to other cities?
Darby ranks #66 out of 115 cities in Montana (better than 43% of state cities) and #12108 out of 15744 cities nationally (23th percentile). The grade of C reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.