Hardness
Very Hard
274 PPM · 16 GPG
Local water dashboard
Official source aggregationWater quality in Grinnell, IA 50112
A source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for Poweshiek County.
2 reported benchmark flags
- Primary matched system
- Grinnell Water Department
- Source water
- Groundwater
- County
- Poweshiek 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
0.0031 mg/L
21% of action level
Utility match
2 systems
Serves 9,564 people system-wide
Hardness meter
How hard is the water?
Estimated local hardness
USGS hardness classification scale
274 PPM
Soft
0–59Moderate
60–120Hard
121–180Very hard
181+
0–59Moderate
60–120Hard
121–180Very hard
181+
Parts per million
274
mg/L as CaCO₃ equivalent
Grains per gallon
16
1 GPG ≈ 17.1 PPM
What this means at home
At 274 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
10 mi
Observation range
Feb 9, 2016–Mar 3, 2026
Estimate confidence
Moderate
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: 080N14W31BAAA 1997NAWQA Poweshiek County (Well).USGS source documentation ↗
Regional context
Is 50112 typical?
These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.
Grinnell median
274 PPM
About the same1 indexed ZIP readings · Range 274–274 PPM
Iowa median
281 PPM
7 PPM lower721 indexed ZIP readings · Range 182–834 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 pass2 fail
Lead (PB90)
0.0031 mg/L
Reported Dec 31, 2025
Copper (CU90)
Not available
No numerical 90th-percentile result
Numerical coverage
3 comparable results
Missing values remain blank; absence is not treated as a pass.
Lead (90th percentile)
Measured in mg/L
Local 0.0031
EPA limit 0.015
Combined Radium (-226 and -228)
Measured in PCI/L
Local 8.13
EPA limit 5
Gross Alpha, Excl. Radon and U
Measured in PCI/L
Local 22
EPA limit 15
Share of EPA benchmark
100% line = listed limit
2026Q2
- All records
- 22
- Health-based
- 14
- Active health-based
- 0
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| Combined Radium (-226 and -228)Health-basedReported 8.13 PCI/L · MCL 5 | IA7930008 | Archived | Jan 1, 2026through Mar 31, 2026 |
| Combined Radium (-226 and -228)Health-basedReported 7.79 PCI/L · MCL 5 | IA7930008 | Archived | Oct 1, 2025through Dec 31, 2025 |
| Gross Alpha, Excl. Radon and U | IA7930008 | Archived | Jul 1, 2025through Sep 30, 2025 |
| Combined Radium (-226 and -228) | IA7930008 | Archived | Jul 1, 2025through Sep 30, 2025 |
| Combined Radium (-226 and -228)Health-basedReported 6.4 PCI/L · MCL 5 | IA7930008 | Archived | Apr 1, 2025through Jun 30, 2025 |
| Combined Radium (-226 and -228)Health-basedReported 6.45 PCI/L · MCL 5 | IA7930008 | Archived | Jan 1, 2025through Mar 31, 2025 |
| Gross Alpha, Excl. Radon and UHealth-basedReported 22 PCI/L · MCL 15 | IA7930008 | Archived | Jan 1, 2025through Mar 31, 2025 |
| Public Notice | IA7930008 | Resolved | Dec 17, 2024through Jul 1, 2024 |
| Combined Radium (-226 and -228)Health-basedReported 7.325 PCI/L · MCL 5 | IA7930008 | Archived | Oct 1, 2024through Dec 31, 2024 |
| Gross Alpha, Excl. Radon and UHealth-basedReported 21.8 PCI/L · MCL 15 | IA7930008 | Archived | Oct 1, 2024through Dec 31, 2024 |
| Revised Total Coliform RuleHealth-based | IA7930601 | Resolved | Sep 1, 2024through Oct 17, 2024 |
| Combined Radium (-226 and -228)Health-basedReported 7.94 PCI/L · MCL 5 | IA7930008 | Archived | Jul 1, 2024through Sep 30, 2024 |
| Gross Alpha, Excl. Radon and UHealth-basedReported 20.5 PCI/L · MCL 15 | IA7930008 | Archived | Jul 1, 2024through Sep 30, 2024 |
| Gross Alpha, Excl. Radon and UHealth-basedReported 20.1 PCI/L · MCL 15 | IA7930008 | Archived | Apr 1, 2024through Jun 30, 2024 |
| Combined Radium (-226 and -228)Health-basedReported 8.36 PCI/L · MCL 5 | IA7930008 | Archived | Apr 1, 2024through Jun 30, 2024 |
| Public Notice | IA7930601 | Unaddressed | Jan 22, 2024 |
| Gross Alpha, Excl. Radon and UHealth-basedReported 15.65 PCI/L · MCL 15 | IA7930008 | Archived | Jan 1, 2024through Mar 31, 2024 |
| Combined Radium (-226 and -228)Health-basedReported 6.2 PCI/L · MCL 5 | IA7930008 | Archived | Jan 1, 2024through Mar 31, 2024 |
| Revised Total Coliform Rule | IA7930601 | Resolved | Sep 1, 2023through Sep 30, 2023 |
| Combined Radium (-226 and -228) | IA7930008 | 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 Grinnell ZIP 50112 using 274 PPM nearby hardness and 3 reported measurement benchmarks.
Scale protection
High-Capacity Whole House Water Softener
274 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 systemsDrinking water protection
Under-Sink Reverse Osmosis System
Combined Radium (-226 and -228), Gross Alpha, Excl. Radon and U have 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 Grinnell
Is tap water safe in Grinnell?+
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 274 PPM, or 16 grains per gallon, classified as very hard. This is not a household tap measurement.
Do I need a water softener?+
At 274 PPM, a correctly sized whole-house softener can reduce scale and hard-water spotting. It does not replace contaminant filtration.