Hardness
Very Hard
371 PPM · 21.7 GPG
Local water dashboard
Official source aggregationWater quality in Madison, WI 53726
A source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for Dane County.
1 reported benchmark flag
- Primary matched system
- Madison Water Utility
- Source water
- Groundwater
- County
- Dane 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
0.007 mg/L
47% of action level
Utility match
10 systems
Serves 272,000 people system-wide
Hardness meter
How hard is the water?
Estimated local hardness
USGS hardness classification scale
371 PPM
Soft
0–59Moderate
60–120Hard
121–180Very hard
181+
0–59Moderate
60–120Hard
121–180Very hard
181+
Parts per million
371
mg/L as CaCO₃ equivalent
Grains per gallon
21.7
1 GPG ≈ 17.1 PPM
What this means at home
At 371 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
57
Nearest site
31.5 mi
Observation range
Aug 3, 2016–Aug 20, 2024
Estimate confidence
Low
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: CO-12/09E/11-0740 (Well).USGS source documentation ↗
Regional context
Is 53726 typical?
These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.
Madison median
375 PPM
About the same13 indexed ZIP readings · Range 365.5–394 PPM
Wisconsin median
288 PPM
83 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 pass1 fail
Lead (PB90)
0.007 mg/L
Reported Sep 30, 2025
Copper (CU90)
1.6 mg/L
Reported Sep 30, 2017
Numerical coverage
2 comparable results
Missing values remain blank; absence is not treated as a pass.
Lead (90th percentile)
Measured in mg/L
Local 0.007
EPA limit 0.015
Copper (90th percentile)
Measured in mg/L
Local 1.6
EPA limit 1.3
Share of EPA benchmark
100% line = listed limit
2026Q2
- All records
- 37
- Health-based
- 3
- Active health-based
- 0
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| Lead and Copper Rule | WI1130244 | Resolved | Jan 1, 2025through Jan 24, 2025 |
| Lead and Copper Rule | WI1132627 | Resolved | Jan 1, 2025through Jan 29, 2025 |
| Revised Total Coliform RuleHealth-based | WI1130232 | Resolved | Nov 17, 2024through Dec 5, 2024 |
| Revised Total Coliform Rule | WI1130232 | Resolved | Nov 17, 2024through Dec 5, 2024 |
| Public Notice | WI1130224 | Unaddressed | Oct 17, 2024 |
| LEAD AND COPPER RULE REVISIONSHealth-based | WI1130224 | Resolved | Oct 17, 2024through Dec 13, 2024 |
| Public Notice | WI1130236 | Unaddressed | Oct 17, 2024 |
| Public Notice | WI1130234 | Unaddressed | Oct 17, 2024 |
| Public Notice | WI1130232 | Unaddressed | Oct 17, 2024 |
| Public Notice | WI1130232 | Unaddressed | Oct 17, 2024 |
| LEAD AND COPPER RULE REVISIONS | WI1130232 | Resolved | Oct 17, 2024through Nov 1, 2024 |
| LEAD AND COPPER RULE REVISIONSHealth-based | WI1130232 | Resolved | Oct 17, 2024through Oct 2, 2025 |
| Consumer Confidence Rule | WI1130236 | Resolved | Jul 1, 2024through Aug 12, 2024 |
| Consumer Confidence Rule | WI1130236 | Resolved | Jul 1, 2024through Aug 12, 2024 |
| Consumer Confidence Rule | WI1130232 | Resolved | Jul 1, 2024through Jul 13, 2024 |
| Consumer Confidence Rule | WI1130232 | Resolved | Jul 1, 2024through Jul 22, 2024 |
| Consumer Confidence Rule | WI1130244 | Resolved | Jul 1, 2024through Jul 22, 2024 |
| Consumer Confidence Rule | WI1133471 | Resolved | Jul 1, 2024through Aug 19, 2024 |
| Consumer Confidence Rule | WI1133471 | Resolved | Jul 1, 2024through Aug 19, 2024 |
| Consumer Confidence Rule | WI1133471 | Resolved | Jul 1, 2023through Mar 4, 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
Your personalized water action plan
Matched to Madison ZIP 53726 using 371 PPM nearby hardness and 2 reported measurement benchmarks.
Scale protection
High-Capacity Whole House Water Softener
371 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 systemsDrinking water protection
Under-Sink Reverse Osmosis System
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.
Nearby indexed reports
Compare ZIPs in Madison
Estimates can differ across a city because monitoring locations and associated systems differ.
Frequently asked
Water questions for Madison
Is tap water safe in Madison?+
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 371 PPM, or 21.7 grains per gallon, classified as very hard. This is not a household tap measurement.
Do I need a water softener?+
At 371 PPM, a correctly sized whole-house softener can reduce scale and hard-water spotting. It does not replace contaminant filtration.