Is Big Sandy, MT Tap Water Safe to Drink?
Graded A, with 3 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
90.4/100
waterverge.com Big Sandy, MT — Water Quality Report
Big Sandy's drinking water received a grade of A (90.4 out of 100), indicating excellent water quality. The city's 1 water system serves approximately 608 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 28 violations on record, including 2 health-based violations. 3 remain unresolved.
What to know about Big Sandy's water
Big Sandy ranks #6 out of 115 cities in Montana for water quality, placing it one of the best in the state.
Big Sandy 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, Big Sandy may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Big Sandy, MT water safe to drink?
Big Sandy's drinking water has significant quality concerns based on EPA testing data. With a grade of A (90.4/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 608 residents using groundwater (wells).
Recent water quality updates for Big Sandy
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Big Sandy's water quality assessment. Grade: A (90.4/100).
Contaminants: Consumer Confidence Rule.
Contaminants: Nitrate-Nitrite.
Contaminants: TTHM, Total Haloacetic Acids (HAA5).
Federal disaster declaration (FEMA DR-4127). 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 Big Sandy's water supply.
Well within EPA limits.
Violation history
Big Sandy's water system has 28 total violations on record, including 2 health-based violations. 3 remain unresolved. 2 violations were issued in the last 5 years.
Flood & environmental risk
Chouteau County has experienced 3 federally declared disasters since 1986. 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 Boxelder Creek At Box Elder.
Where does Big Sandy's water come from?
Big Sandy's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 608 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Boxelder Creek At Box Elder (river).
What Big Sandy residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Big Sandy'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.
Big Sandy'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
Drought conditions
D3 — extreme droughtChouteau County is currently in D3 (extreme drought) per the U.S. Drought Monitor (week of May 5, 2026). Drought can elevate disinfection-byproduct (TTHM/HAA5) levels and taste/odor issues as utilities draw from lower reservoirs.
Source: U.S. Drought Monitor, updated weekly by NDMC, USDA, and NOAA.
Flood & disaster history
Chouteau County has experienced 3 federally declared disasters since 1986. 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. | 0.0 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Big Sandy compares by contaminant
Explore where Big Sandy ranks among all Montana cities for specific contaminants.
Water source & infrastructure
Where Big Sandy's water comes from
Big Sandy'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 608 people through 1 water system.
Water bodies near Big Sandy
Big Sandy is located near 1 notable water body. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Big Sandy
| System Name | PWSID | Population | Source |
|---|---|---|---|
| BIG SANDY TOWN OF | MT0000150 | 608 | GW |
How Big Sandy compares
Full Montana rankings →Big Sandy's score of 90.4/100 is above the average of 45/100 among major Montana cities. It outscores 10 of 10 nearby cities.
Nearby cities
View Montana rankings →About Big Sandy, MT
Wikipedia →Big Sandy is a town in Chouteau County, Montana, United States. The population was 605 at the 2020 census.
Learn more about your water
Guides and resources related to Big Sandy's water quality findings.
Explore water quality across Chouteau
Frequently asked questions
Is Big Sandy, MT tap water safe to drink?
Big Sandy's water quality earned a grade of A (90.4/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #6 out of 115 cities tested in Montana.
What contaminants are in Big Sandy's water?
Lead was measured at 0.0 ppb (90th percentile). 28 violations are on record.
How is Big Sandy'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 Big Sandy?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Big Sandy's water come from?
Big Sandy's water is sourced from Groundwater. The city has 1 water system serving approximately 608 residents.
What health violations has Big Sandy's water system had?
Big Sandy has 2 health-based violations on record. The most recent violation was recorded in July 2024. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 3 violations remain unresolved.
Is Big Sandy's groundwater at risk of contamination?
Big Sandy 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 28 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 Big Sandy's water compare to other cities?
Big Sandy ranks #6 out of 115 cities in Montana (better than 95% of state cities) and #2265 out of 15744 cities nationally (86th percentile). The grade of A reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Big Sandy's small water system affect quality?
Big Sandy's system serves approximately 608 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 28 violations on record.