Hardness
Very Hard
240 PPM · 14 GPG
Local water dashboard
Official source aggregationWater quality in Ann Arbor, MI 48103
A source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for Washtenaw County.
No active health-based violation reported
- Primary matched system
- Ann Arbor
- Source water
- Surface water + Groundwater
- County
- Washtenaw 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 mg/L
0% of action level
Utility match
7 systems
Serves 123,851 people system-wide
Hardness meter
How hard is the water?
Estimated local hardness
USGS hardness classification scale
240 PPM
Soft
0–59Moderate
60–120Hard
121–180Very hard
181+
0–59Moderate
60–120Hard
121–180Very hard
181+
Parts per million
240
mg/L as CaCO₃ equivalent
Grains per gallon
14
1 GPG ≈ 17.1 PPM
What this means at home
At 240 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
3
Nearest site
48.4 mi
Observation range
Jan 7, 2016–Jun 9, 2026
Estimate confidence
Low
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: CLINTON RIVER AT STERLING HEIGHTS, MI (Stream).USGS source documentation ↗
Regional context
Is 48103 typical?
These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.
Ann Arbor median
240 PPM
About the same5 indexed ZIP readings · Range 240–240 PPM
Michigan median
283 PPM
43 PPM lower504 indexed ZIP readings · Range 41.3–459.5 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 mg/L
Reported Dec 31, 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
EPA limit 0.015
Share of EPA benchmark
100% line = listed limit
2026Q2
- All records
- 12
- Health-based
- 0
- Active health-based
- 0
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| LEAD AND COPPER RULE REVISIONS | MI0003940 | Unaddressed | Jul 2, 2025 |
| LEAD AND COPPER RULE REVISIONS | MI0000430 | Resolved | Jul 2, 2025through Jan 2, 2026 |
| Consumer Confidence Rule | MI0005360 | Resolved | Jul 1, 2025through Dec 15, 2025 |
| Revised Total Coliform Rule | MI0005977 | Resolved | Nov 11, 2024through Dec 2, 2024 |
| Consumer Confidence Rule | MI0000430 | Resolved | Jul 1, 2024through Dec 3, 2024 |
| Revised Total Coliform Rule | MI0005977 | Resolved | Nov 11, 2023through Nov 27, 2023 |
| TTHM | MI0005360 | Resolved | Oct 1, 2023through Dec 31, 2023 |
| Total Haloacetic Acids (HAA5) | MI0005360 | Resolved | Oct 1, 2023through Dec 31, 2023 |
| Lead and Copper Rule | MI0003940 | Resolved | Oct 1, 2023through May 6, 2024 |
| Lead and Copper Rule | MI0005977 | Resolved | Oct 11, 2022through Dec 19, 2022 |
| Total Haloacetic Acids (HAA5) | MI0005360 | Resolved | Oct 1, 2022through Dec 31, 2022 |
| Consumer Confidence Rule | MI0005977 | Resolved | Jul 1, 2021through Sep 29, 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 Ann Arbor ZIP 48103 using 240 PPM nearby hardness and 1 reported measurement benchmarks.
Scale protection
High-Capacity Whole House Water Softener
240 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 Ann Arbor
Estimates can differ across a city because monitoring locations and associated systems differ.
Frequently asked
Water questions for Ann Arbor
Is tap water safe in Ann Arbor?+
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 240 PPM, or 14 grains per gallon, classified as very hard. This is not a household tap measurement.
Do I need a water softener?+
At 240 PPM, a correctly sized whole-house softener can reduce scale and hard-water spotting. It does not replace contaminant filtration.