Hardness
Very Hard
400.5 PPM · 23.4 GPG
Local water dashboard
Official source aggregationWater quality in Janesville, WI 53546
A source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for Rock County.
No active health-based violation reported
- Primary matched system
- Janesville Water Utility
- Source water
- Groundwater
- County
- Rock 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
6.7e-4 mg/L
4% of action level
Utility match
3 systems
Serves 64,415 people system-wide
Hardness meter
How hard is the water?
Estimated local hardness
USGS hardness classification scale
400.5 PPM
Soft
0–59Moderate
60–120Hard
121–180Very hard
181+
0–59Moderate
60–120Hard
121–180Very hard
181+
Parts per million
400.5
mg/L as CaCO₃ equivalent
Grains per gallon
23.4
1 GPG ≈ 17.1 PPM
What this means at home
At 400.5 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
74
Nearest site
20.6 mi
Observation range
Aug 3, 2016–Aug 8, 2024
Estimate confidence
Moderate
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: 46N5E-21.1d1 (1-CHE-S) (Well).USGS source documentation ↗
Regional context
Is 53546 typical?
These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.
Janesville median
396 PPM
5 PPM higher3 indexed ZIP readings · Range 396–400.5 PPM
Wisconsin median
288 PPM
113 PPM higher556 indexed ZIP readings · Range 41.3–467 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 pass
Lead (PB90)
6.7e-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.
Lead (90th percentile)
Measured in mg/L
Local 6.7e-4
EPA limit 0.015
Share of EPA benchmark
100% line = listed limit
2026Q2
- All records
- 8
- Health-based
- 1
- Active health-based
- 0
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| LEAD AND COPPER RULE REVISIONSHealth-based | WI1540111 | Resolved | Oct 17, 2024through Apr 21, 2025 |
| Public Notice | WI1540111 | Unaddressed | Oct 17, 2024 |
| Consumer Confidence Rule | WI1540111 | Resolved | Jul 1, 2023through Jul 21, 2023 |
| Consumer Confidence Rule | WI1540111 | Resolved | Jul 1, 2023through Jul 21, 2023 |
| Lead and Copper Rule | WI1540111 | Resolved | Jan 1, 2022through Feb 28, 2022 |
| Lead and Copper Rule | WI1540111 | Unaddressed | Jan 1, 2013 |
| Public Notice | WI1540111 | Unaddressed | Feb 1, 2010 |
| Public Notice | WI1540111 | Unaddressed | Jan 1, 2010 |
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 Janesville ZIP 53546 using 400.5 PPM nearby hardness and 1 reported measurement benchmarks.
Scale protection
High-Capacity Whole House Water Softener
400.5 PPM is 3× 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.
Nearby indexed reports
Compare ZIPs in Janesville
Estimates can differ across a city because monitoring locations and associated systems differ.
Frequently asked
Water questions for Janesville
Is tap water safe in Janesville?+
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 400.5 PPM, or 23.4 grains per gallon, classified as very hard. This is not a household tap measurement.
Do I need a water softener?+
At 400.5 PPM, a correctly sized whole-house softener can reduce scale and hard-water spotting. It does not replace contaminant filtration.