Is Great Falls, MT Tap Water Safe to Drink?
Yes, Great Falls tap water is safe to drink. Hardness is low at 71 PPM, and no contaminants exceed health guidelines. Most homes here don't need treatment.
Hardness Scale: Where Great Falls Falls
0Slightly
60Moderate
120Hard
180Very Hard
250Extreme
400+
How Great Falls Compares
Great Falls's water is 49% softer than the national average of 138 PPM - ranking in the bottom 63% for hardness nationwide. Most homes here do not need a softener. Within Montana, it ranks #4 of 8 cities (4% below the state average of 74 PPM). Among cities (50k-100k), Great Falls ranks #179 of 258 for hardness.
What Great Falls's Water Means for Your Home
Hardness: 71 PPM - Low Concern
Great Falls's water is moderately hard at 71 PPM. You'll see some spotting on glassware and a film on shower doors over time, but it's not the kind of hardness that demands a full softener. A salt-free conditioner is worth considering if you have a tankless water heater or high-end fixtures.
Contaminants & Safety
Lead levels deserve attention. At 8 ppb, Great Falls is above the ideal of zero, though below the EPA action level of 15 ppb (dropping to 10 ppb in November 2027 under the Lead and Copper Rule Improvements). The lead typically comes from aging service lines or interior plumbing, not the treatment plant. A point-of-use filter certified for lead at the kitchen faucet is a practical safeguard, especially in older homes.
What's in the Treatment Process
Great Falls's surface water supply requires heavy chlorination to stay safe — but that creates a tradeoff. The treatment process generates disinfection byproducts: TTHMs at 39.3 ppb (49% of the legal limit, but 262x the EWG guideline) and HAA5 at 29.2 ppb (49% of the legal limit, but 292x the EWG guideline). These are within legal limits, but the EWG sets much tighter thresholds based on cancer-risk research. A whole-house activated carbon filter reduces both chlorine and byproducts. All measurements are within federal legal limits. The EWG guidelines represent a more conservative, health-based standard.
| Contaminant | Detected | Health Guideline | Legal Limit | Status |
|---|---|---|---|---|
| Hardness (as CaCO₃) | 71 PPM | < 60 PPM | No federal limit | ✓ OK |
| Total Dissolved Solids | 94 PPM | < 300 PPM | 500 PPM | ✓ OK |
| PFAS (total) | 0 ppt | — | No total limit | ✓ ND |
| ↳ PFOA | 0 ppt | 0 ppt | 4 ppt (2024) | ✓ OK |
| ↳ PFOS | 0 ppt | 0 ppt | 4 ppt (2024) | ✓ OK |
| Lead | 8 ppb | 0 ppb (no safe level) | 15 ppb (10 ppb in 2027) | ⚠ Elevated |
| Chlorine / Chloramine | 0.7 mg/L | Taste threshold ~1.0 | 4.0 mg/L | ✓ Normal |
| Nitrate | 0.04 mg/L | 5 mg/L | 10 mg/L | ✓ OK |
Recommendations for Great Falls Homes
How to Test Your Water in Great Falls
Lead enters water from your home's plumbing, not the treatment plant — so Great Falls's city-wide average of 8 ppb may not match your tap. Testing your specific faucet is the only way to know. Run cold water for 30 seconds before collecting a sample.
Free option: Request City of Great Falls's annual Consumer Confidence Report for official city-level data.
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About Great Falls's Water Supply
Water Utility: City of Great Falls
Water Source: Missouri River (Surface Water)
Population Served: 60,000
Hardness: 71 PPM (4.2 grains per gallon)
Great Falls's drinking water comes from surface sources — Missouri River. Surface water requires more extensive treatment than groundwater, including coagulation, filtration, and disinfection. This heavier chlorination is why disinfection byproducts tend to be higher in surface-supplied systems. On the upside, surface sources often deliver softer water than deep aquifers. The system serves 60,000 residents.
Water quality can vary by neighborhood and season. For your exact numbers, request City of Great Falls's Consumer Confidence Report (CCR) or test your own tap.
ZIP Codes Covered by This Report
This water quality data applies to all areas served by City of Great Falls in Great Falls, MT, including ZIP codes:
59401, 59402, 59403, 59404, 59405, 59406, 59410, 59412, 59414, 59416, 59418, 59419, 59420, 59421, 59422, 59424, 59425, 59427, 59430, 59432, 59433, 59435, 59436, 59440, 59442, 59443, 59446, 59447, 59450, 59452, 59454, 59456, 59457, 59460, 59461, 59462, 59463, 59464, 59465, 59466, 59467, 59468, 59469, 59472, 59474, 59477, 59479, 59480, 59482, 59483, 59484, 59485, 59486, 59487
If your ZIP code is listed above, this report covers your water supply. Water quality may vary slightly by neighborhood.
Compare Great Falls to Other Montana Cities
Frequently Asked Questions About Great Falls Water
Is Great Falls tap water safe to drink?
Where does Great Falls's water come from?
Do I need a water softener in Great Falls?
What water filter is best for Great Falls?
What is the hardness of Great Falls water in grains per gallon?
Is Great Falls water safe for babies and infants?
What are disinfection byproducts in Great Falls's water?
Can I drink Great Falls tap water straight from the faucet?
Data sources: Lead and copper data from EPA Safe Drinking Water Act LCR reporting. Contaminant data from utility-reported testing results. PFAS data from EPA UCMR5 (2023–2025). Hardness from USGS and municipal reports. Data reflects system-level testing results and may not match your specific tap due to neighborhood plumbing, season, or recent utility changes. For your utility's latest results, request their Consumer Confidence Report (CCR). Our methodology. Last updated: 2026-02-24.
What Great Falls Homeowners Actually Buy
Common purchases for homes with 71 PPM water.
Affiliate disclosure: we may earn a commission. Selection based on Great Falls's water data.