Hardness
Soft
21.7 PPM · 1.3 GPG
Local water dashboard
Official source aggregationWater quality in Great Falls, MT 59405
A source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for Cascade County.
1 reported benchmark flag
- Primary matched system
- Great Falls City Of
- Source water
- Surface water + Groundwater
- County
- Cascade County
- Profile updated
At a glance
What the current records say
EPA quarter 2026Q2
Compliance screen
No active flag
0 active health-based records
Lead 90th percentile
0.012 mg/L
80% of action level
Utility match
10 systems
Serves 60,000 people system-wide
Hardness meter
How hard is the water?
Estimated local hardness
USGS hardness classification scale
21.7 PPM
Soft
0–59Moderate
60–120Hard
121–180Very hard
181+
0–59Moderate
60–120Hard
121–180Very hard
181+
Parts per million
21.7
mg/L as CaCO₃ equivalent
Grains per gallon
1.3
1 GPG ≈ 17.1 PPM
What this means at home
At 21.7 PPM, mineral scale can build up on fixtures and heating elements, reduce soap lather, and leave visible spotting. Hardness is primarily an aesthetic and appliance concern—not itself a tap-water safety rating.
USGS sites used
19
Nearest site
38.7 mi
Observation range
May 10, 2016–Sep 18, 2024
Estimate confidence
Low
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: Sheep Cr ab Moose Cr, nr White Sulphur Springs, MT (Stream).USGS source documentation ↗
Regional context
Is 59405 typical?
These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.
Great Falls median
164 PPM
142 PPM lower3 indexed ZIP readings · Range 21.7–164 PPM
Montana median
122 PPM
100 PPM lower129 indexed ZIP readings · Range 0.2–799.5 PPM
EPA benchmark screen
Contaminant snapshot
Available numerical results from associated SDWIS community water systems, compared with the applicable action level or federal MCL. Federal measured-value coverage is incomplete.
1 pass1 fail
Lead (PB90)
0.012 mg/L
Reported Jun 30, 2026
Copper (CU90)
2.21 mg/L
Reported Dec 31, 2018
Numerical coverage
2 comparable results
Missing values remain blank; absence is not treated as a pass.
Lead (90th percentile)
Measured in mg/L
Local 0.012
EPA limit 0.015
Copper (90th percentile)
Measured in mg/L
Local 2.21
EPA limit 1.3
Share of EPA benchmark
100% line = listed limit
2026Q2
- All records
- 163
- Health-based
- 3
- Active health-based
- 0
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| Revised Total Coliform Rule | MT0005164 | Resolved | Dec 1, 2025through Dec 31, 2025 |
| E. COLI | MT0000232 | Resolved | Jul 22, 2025through Jul 24, 2025 |
| Revised Total Coliform Rule | MT0000028 | Resolved | Jul 1, 2025through Jul 31, 2025 |
| Consumer Confidence Rule | MT0000028 | Resolved | Jul 1, 2025through Jul 17, 2025 |
| Revised Total Coliform Rule | MT0000028 | Resolved | Jun 1, 2025through Jun 30, 2025 |
| Nitrate-Nitrite | MT0000571 | Resolved | Jan 1, 2025through Dec 31, 2025 |
| Nitrate-Nitrite | MT0000028 | Resolved | Jan 1, 2025through Mar 31, 2025 |
| Nitrate-Nitrite | MT0004261 | Resolved | Jan 1, 2025through Dec 31, 2025 |
| Nitrate-Nitrite | MT0004419 | Resolved | Jan 1, 2025through Dec 31, 2025 |
| Lead and Copper Rule | MT0003539 | Resolved | Dec 30, 2024through Jul 1, 2025 |
| Lead and Copper Rule | MT0000050 | Resolved | Dec 30, 2024through Jan 12, 2026 |
| Revised Total Coliform Rule | MT0000515 | Resolved | Nov 1, 2024through Nov 30, 2024 |
| Surface Water Treatment Rule | MT0000053 | Resolved | Nov 1, 2024through Nov 30, 2024 |
| Groundwater RuleHealth-based | MT0005164 | Resolved | Oct 18, 2024through Nov 8, 2024 |
| Consumer Confidence Rule | MT0003539 | Unaddressed | Oct 1, 2024 |
| Revised Total Coliform Rule | MT0005164 | Resolved | Oct 1, 2024through Oct 31, 2024 |
| Consumer Confidence Rule | MT0003539 | Resolved | Jul 1, 2024through Jul 1, 2025 |
| Endrin | MT0000232 | Resolved | Jul 1, 2024through Sep 30, 2024 |
| BHC-GAMMA | MT0000232 | Resolved | Jul 1, 2024through Sep 30, 2024 |
| Toxaphene | MT0000232 | Resolved | Jul 1, 2024through Sep 30, 2024 |
No reported violation does not prove that every contaminant was tested or absent; SDWIS measured values are incomplete and lag state records.
Solutions matcher
Your personalized water action plan
Matched to Great Falls ZIP 59405 using 21.7 PPM nearby hardness and 2 reported measurement benchmarks.
Drinking water protection
Under-Sink Reverse Osmosis System
Copper (90th percentile) has a measured benchmark flag or active health-based SDWIS record in this profile.
A certified multi-stage RO system targets a broader range of dissolved contaminants at the kitchen tap.
Explore under-sink filtrationAffiliate disclosure: we may earn a commission from qualifying purchases, at no added cost to you. Product matching is educational and does not replace certified water testing.
Nearby indexed reports
Compare ZIPs in Great Falls
Estimates can differ across a city because monitoring locations and associated systems differ.
Frequently asked
Water questions for Great Falls
Is tap water safe in Great Falls?+
EPA ECHO shows no active health-based violation for the associated systems in this reporting snapshot. This does not prove every contaminant is absent; federal records can lag and household plumbing can change tap conditions.
How hard is the water?+
Nearby USGS observations produce an estimate of 21.7 PPM, or 1.3 grains per gallon, classified as soft. This is not a household tap measurement.
Do I need a water softener?+
There is no high-hardness trigger in this profile. Confirm with a tap test before buying equipment.