Hardness
Moderately Hard
93.7 PPM · 5.5 GPG
Local water dashboard
Official source aggregationA source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for Stillwater County.
At a glance
EPA quarter 2026Q2
Hardness
Moderately Hard
93.7 PPM · 5.5 GPG
Compliance screen
No active flag
0 active health-based records
Lead 90th percentile
0.003 mg/L
20% of action level
Utility match
1 system
Serves 70 people system-wide
Hardness meter
Estimated local hardness
USGS hardness classification scale
93.7 PPM
Parts per million
93.7
mg/L as CaCO₃ equivalent
Grains per gallon
5.5
1 GPG ≈ 17.1 PPM
What this means at home
At 93.7 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
7
Nearest site
56.3 mi
Observation range
Feb 25, 2016–Sep 10, 2025
Estimate confidence
Low
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: Lodgepole Cr at mouth, nr Wilsall, MT (Stream).USGS source documentation ↗
Regional context
These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.
Rapelje median
94 PPM
About the same1 indexed ZIP readings · Range 93.7–93.7 PPM
Montana median
122 PPM
28 PPM lower129 indexed ZIP readings · Range 0.2–799.5 PPM
EPA benchmark screen
Available numerical results from associated SDWIS community water systems, compared with the applicable action level or federal MCL. Federal measured-value coverage is incomplete.
Lead (PB90)
0.003 mg/L
Reported Dec 31, 2025
Copper (CU90)
2.36 mg/L
Reported Dec 31, 2013
Numerical coverage
2 comparable results
Missing values remain blank; absence is not treated as a pass.
Measured in mg/L
Local 0.003
EPA limit 0.015
Measured in mg/L
Local 2.36
EPA limit 1.3
100% line = listed limit
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| Nitrate-Nitrite | MT0000313 | Resolved | Jul 1, 2024through Sep 30, 2024 |
| Lead and Copper Rule | MT0000313 | Unaddressed | Jan 1, 1997 |
No reported violation does not prove that every contaminant was tested or absent; SDWIS measured values are incomplete and lag state records.
Solutions matcher
Matched to Rapelje ZIP 59067 using 93.7 PPM nearby hardness and 2 reported measurement benchmarks.
Drinking water protection
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.
Frequently asked
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.
Nearby USGS observations produce an estimate of 93.7 PPM, or 5.5 grains per gallon, classified as moderately hard. This is not a household tap measurement.
There is no high-hardness trigger in this profile. Confirm with a tap test before buying equipment.