Hardness
Very Hard
248.5 PPM · 14.5 GPG
Local water dashboard
Official source aggregationWater quality in Oshkosh, WI 54902
A source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for Winnebago County.
No active health-based violation reported
- Primary matched system
- Oshkosh Waterworks
- Source water
- Surface water + Groundwater
- County
- Winnebago 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
0.0061 mg/L
41% of action level
Utility match
2 systems
Serves 63,000 people system-wide
Hardness meter
How hard is the water?
Estimated local hardness
USGS hardness classification scale
248.5 PPM
Soft
0–59Moderate
60–120Hard
121–180Very hard
181+
0–59Moderate
60–120Hard
121–180Very hard
181+
Parts per million
248.5
mg/L as CaCO₃ equivalent
Grains per gallon
14.5
1 GPG ≈ 17.1 PPM
What this means at home
At 248.5 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
12
Nearest site
21 mi
Observation range
Jan 11, 2016–Jun 10, 2026
Estimate confidence
Moderate
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: GREEN LAKE INLET AT CT HIGHWAY A NR GREEN LAKE, WI (Stream).USGS source documentation ↗
Regional context
Is 54902 typical?
These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.
Oshkosh median
243 PPM
6 PPM higher4 indexed ZIP readings · Range 243–248.5 PPM
Wisconsin median
288 PPM
39 PPM lower556 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)
0.0061 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 0.0061
EPA limit 0.015
Share of EPA benchmark
100% line = listed limit
2026Q2
- All records
- 1
- Health-based
- 0
- Active health-based
- 0
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| Bromate | WI4710457 | Resolved | Jul 1, 2023through Sep 30, 2023 |
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 Oshkosh ZIP 54902 using 248.5 PPM nearby hardness and 1 reported measurement benchmarks.
Scale protection
High-Capacity Whole House Water Softener
248.5 PPM is 2× 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 Oshkosh
Estimates can differ across a city because monitoring locations and associated systems differ.
Frequently asked
Water questions for Oshkosh
Is tap water safe in Oshkosh?+
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 248.5 PPM, or 14.5 grains per gallon, classified as very hard. This is not a household tap measurement.
Do I need a water softener?+
At 248.5 PPM, a correctly sized whole-house softener can reduce scale and hard-water spotting. It does not replace contaminant filtration.