Hardness
Moderately Hard
81.3 PPM · 4.8 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 Marquette County.
At a glance
EPA quarter 2026Q2
Hardness
Moderately Hard
81.3 PPM · 4.8 GPG
Compliance screen
No active flag
0 active health-based records
Lead 90th percentile
0.0012 mg/L
8% of action level
Utility match
1 system
Serves 250 people system-wide
Hardness meter
Estimated local hardness
USGS hardness classification scale
81.3 PPM
Parts per million
81.3
mg/L as CaCO₃ equivalent
Grains per gallon
4.8
1 GPG ≈ 17.1 PPM
What this means at home
At 81.3 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
17
Nearest site
42.6 mi
Observation range
May 16, 2016–Sep 12, 2024
Estimate confidence
Low
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: 45N 30W 20ADA 01 (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.
Rock median
81 PPM
About the same1 indexed ZIP readings · Range 81.3–81.3 PPM
Michigan median
283 PPM
202 PPM lower504 indexed ZIP readings · Range 41.3–459.5 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)
0.0012 mg/L
Reported Dec 31, 2024
Copper (CU90)
1.58 mg/L
Reported Dec 31, 1993
Numerical coverage
2 comparable results
Missing values remain blank; absence is not treated as a pass.
Measured in mg/L
Local 0.0012
EPA limit 0.015
Measured in mg/L
Local 1.58
EPA limit 1.3
100% line = listed limit
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| Combined Uranium | MI0004063 | Resolved | Jan 1, 2024through Sep 30, 2024 |
| Consumer Confidence Rule | MI0004063 | Resolved | Jul 1, 2023through Jan 26, 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
Matched to Rock ZIP 49880 using 81.3 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 81.3 PPM, or 4.8 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.