Hardness
Very Hard
429 PPM · 25.1 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 Ozaukee County.
At a glance
EPA quarter 2026Q2
Hardness
Very Hard
429 PPM · 25.1 GPG
Compliance screen
No active flag
0 active health-based records
Lead 90th percentile
7.5e-4 mg/L
5% of action level
Utility match
3 systems
Serves 12,269 people system-wide
Hardness meter
Estimated local hardness
USGS hardness classification scale
429 PPM
Parts per million
429
mg/L as CaCO₃ equivalent
Grains per gallon
25.1
1 GPG ≈ 17.1 PPM
What this means at home
At 429 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
41
Nearest site
13.1 mi
Observation range
Jun 15, 2020–Aug 20, 2024
Estimate confidence
Moderate
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: WN-10/19E/13-0997 (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.
Grafton median
429 PPM
About the same1 indexed ZIP readings · Range 429–429 PPM
Wisconsin median
288 PPM
141 PPM higher556 indexed ZIP readings · Range 41.3–467 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)
7.5e-4 mg/L
Reported Sep 30, 2024
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 7.5e-4
EPA limit 0.015
100% line = listed limit
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| LEAD AND COPPER RULE REVISIONS | WI2460113 | Resolved | Jul 2, 2025through Jul 23, 2025 |
| LEAD AND COPPER RULE REVISIONS | WI2460114 | Resolved | Oct 17, 2024through Dec 11, 2024 |
| LEAD AND COPPER RULE REVISIONSHealth-based | WI2460114 | Resolved | Oct 17, 2024through Dec 12, 2024 |
| Public Notice | WI2460114 | Unaddressed | Oct 17, 2024 |
| Public Notice | WI2460114 | Unaddressed | Oct 17, 2024 |
| Lead and Copper Rule | WI2460114 | Resolved | Jan 1, 2022through Jun 27, 2023 |
| Lead and Copper Rule | WI2460114 | Resolved | Jun 1, 2021through Sep 21, 2022 |
| Nitrite | WI2460114 | Resolved | Jan 1, 2021through Dec 31, 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 Grafton ZIP 53024 using 429 PPM nearby hardness and 1 reported measurement benchmarks.
Scale protection
429 PPM is 4× the high-hardness trigger used by this matcher.
Designed to reduce scale on fixtures, water heaters, glassware, and plumbing throughout the home.
Compare whole-house systemsAffiliate 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 429 PPM, or 25.1 grains per gallon, classified as very hard. This is not a household tap measurement.
At 429 PPM, a correctly sized whole-house softener can reduce scale and hard-water spotting. It does not replace contaminant filtration.