Hardness
Soft
42.4 PPM · 2.5 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 Dewey County.
At a glance
EPA quarter 2026Q2
Hardness
Soft
42.4 PPM · 2.5 GPG
Compliance screen
No active flag
0 active health-based records
Lead 90th percentile
0.002 mg/L
13% of action level
Utility match
1 system
Serves 166 people system-wide
Hardness meter
Estimated local hardness
USGS hardness classification scale
42.4 PPM
Parts per million
42.4
mg/L as CaCO₃ equivalent
Grains per gallon
2.5
1 GPG ≈ 17.1 PPM
What this means at home
At 42.4 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
6
Nearest site
29.8 mi
Observation range
Jul 27, 2016–May 1, 2024
Estimate confidence
Low
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: 18N22E33BDB (Well).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.
Whitehorse median
42 PPM
About the same1 indexed ZIP readings · Range 42.4–42.4 PPM
South Dakota median
516 PPM
474 PPM lower234 indexed ZIP readings · Range 20.5–1330 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)
0.002 mg/L
Reported Dec 31, 2023
Copper (CU90)
Not available
No numerical 90th-percentile result
Numerical coverage
1 comparable result
Missing values remain blank; absence is not treated as a pass.
Measured in mg/L
Local 0.002
EPA limit 0.015
100% line = listed limit
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| Revised Total Coliform Rule | SD4600143 | Resolved | May 11, 2021through May 17, 2021 |
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 Whitehorse ZIP 57630 using 42.4 PPM nearby hardness and 1 reported measurement benchmarks.
No urgent match
This profile does not trigger a treatment recommendation. Test at the tap before investing in equipment.
Affiliate 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 42.4 PPM, or 2.5 grains per gallon, classified as soft. This is not a household tap measurement.
There is no high-hardness trigger in this profile. Confirm with a tap test before buying equipment.