Is St Ignatius, MT Tap Water Safe to Drink?
Graded B, with 19 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
76.5/100
waterverge.com St Ignatius, MT — Water Quality Report
St Ignatius's drinking water received a grade of B (76.5 out of 100), indicating good water quality. The city's 2 water systems serve approximately 765 residents using groundwater.
Lead levels were measured at 1.0 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 175 violations on record, including 10 health-based violations. 19 remain unresolved.
What to know about St Ignatius's water
St Ignatius ranks #46 out of 115 cities in Montana for water quality, placing it mid-range in the state.
St Ignatius 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, St Ignatius may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is St Ignatius, MT water safe to drink?
St Ignatius's drinking water has significant quality concerns based on EPA testing data. With a grade of B (76.5/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 2 water systems serve approximately 765 residents using groundwater (wells).
Recent water quality updates for St Ignatius
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into St Ignatius's water quality assessment. Grade: B (76.5/100).
Contaminants: Groundwater Rule.
Contaminants: E. COLI.
Contaminants: Nitrate-Nitrite.
Federal disaster declaration (FEMA DR-4437). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-4172). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for St Ignatius's water supply.
Well within EPA limits.
Violation history
St Ignatius's water system has 175 total violations on record, including 10 health-based violations. 19 remain unresolved. 4 violations were issued in the last 5 years.
Flood & environmental risk
Lake County has experienced 3 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 Mission Creek Ab Reservoir Nr St. Ignatius.
Where does St Ignatius's water come from?
St Ignatius's drinking water comes from groundwater (wells), supplied by 2 water systems serving approximately 765 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Mission Creek Ab Reservoir Nr St. Ignatius (river).
What St Ignatius residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in St Ignatius'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.
St Ignatius's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
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
Lake County has experienced 3 federally declared disasters since 2005. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
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. | 1.0 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how St Ignatius compares by contaminant
Explore where St Ignatius ranks among all Montana cities for specific contaminants.
Water source & infrastructure
Where St Ignatius's water comes from
St Ignatius'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 765 people through 2 water systems.
Water bodies near St Ignatius
St Ignatius is located near 1 notable water body. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving St Ignatius
| System Name | PWSID | Population | Source |
|---|---|---|---|
| ST IGNATIUS TOWN OF | MT0001740 | 700 | GW |
| CHRISTIAN CHILDRENS RANCH | MT0003720 | 65 | GW |
How St Ignatius compares
Full Montana rankings →St Ignatius's score of 76.5/100 is above the average of 45/100 among major Montana cities. It outscores 9 of 10 nearby cities.
Nearby cities
View Montana rankings →About St Ignatius, MT
Wikipedia →St. Ignatius or Saint Ignatius is a town in Lake County, Montana, United States. The population was 768 at the 2020 census. The town is located on the Flathead Indian Reservation.
Learn more about your water
Guides and resources related to St Ignatius's water quality findings.
Explore water quality across Lake
Frequently asked questions
Is St Ignatius, MT tap water safe to drink?
St Ignatius's water quality earned a grade of B (76.5/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #46 out of 115 cities tested in Montana.
What contaminants are in St Ignatius's water?
Lead was measured at 1.0 ppb (90th percentile). 175 violations are on record.
How is St Ignatius'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 St Ignatius?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does St Ignatius's water come from?
St Ignatius's water is sourced from Groundwater. The city has 2 water systems serving approximately 765 residents.
What health violations has St Ignatius's water system had?
St Ignatius has 10 health-based violations on record. The most recent violation was recorded in September 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 19 violations remain unresolved.
Is St Ignatius's groundwater at risk of contamination?
St Ignatius 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 175 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 St Ignatius's water compare to other cities?
St Ignatius ranks #46 out of 115 cities in Montana (better than 60% of state cities) and #9291 out of 15744 cities nationally (41th percentile). The grade of B reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.