Hardness
Very Hard
411 PPM · 24 GPG
Local water dashboard
Official source aggregationWater quality in Williams Bay, WI 53191
A source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for Walworth County.
1 reported benchmark flag
- Primary matched system
- Williams Bay Waterworks
- Source water
- Groundwater
- County
- Walworth 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
0.016 mg/L
107% of action level
Utility match
1 system
Serves 2,601 people system-wide
Hardness meter
How hard is the water?
Estimated local hardness
USGS hardness classification scale
411 PPM
Soft
0–59Moderate
60–120Hard
121–180Very hard
181+
0–59Moderate
60–120Hard
121–180Very hard
181+
Parts per million
411
mg/L as CaCO₃ equivalent
Grains per gallon
24
1 GPG ≈ 17.1 PPM
What this means at home
At 411 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
73
Nearest site
6.8 mi
Observation range
May 30, 2017–Aug 5, 2024
Estimate confidence
Moderate
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: 2N18E-31.8a (Well).USGS source documentation ↗
Regional context
Is 53191 typical?
These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.
Williams Bay median
411 PPM
About the same1 indexed ZIP readings · Range 411–411 PPM
Wisconsin median
288 PPM
123 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.
0 pass1 fail
Lead (PB90)
0.016 mg/L
Reported Jun 30, 2025
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 0.016
EPA limit 0.015
Share of EPA benchmark
100% line = listed limit
2026Q2
- All records
- 7
- Health-based
- 1
- Active health-based
- 0
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| Public Notice | WI2650060 | Resolved | Sep 11, 2025through Dec 29, 2025 |
| Lead and Copper RuleHealth-based | WI2650060 | Resolved | Jul 1, 2025through Sep 26, 2025 |
| Lead and Copper Rule | WI2650060 | Unaddressed | Jan 1, 2025 |
| Lead and Copper Rule | WI2650060 | Archived | Jan 1, 2025through Jun 30, 2025 |
| Lead and Copper Rule | WI2650060 | Archived | Jan 1, 2025through Jun 30, 2025 |
| Consumer Confidence Rule | WI2650060 | Resolved | Jul 1, 2021through Oct 18, 2021 |
| Consumer Confidence Rule | WI2650060 | Resolved | Jul 1, 2021through Oct 18, 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
Your personalized water action plan
Matched to Williams Bay ZIP 53191 using 411 PPM nearby hardness and 1 reported measurement benchmarks.
Scale protection
High-Capacity Whole House Water Softener
411 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
Lead (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
Water questions for Williams Bay
Is tap water safe in Williams Bay?+
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 411 PPM, or 24 grains per gallon, classified as very hard. This is not a household tap measurement.
Do I need a water softener?+
At 411 PPM, a correctly sized whole-house softener can reduce scale and hard-water spotting. It does not replace contaminant filtration.