Hardness
Very Hard
309 PPM · 18.1 GPG
Local water dashboard
Official source aggregationWater quality in Illiopolis, IL 62539
A source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for Sangamon County.
1 reported benchmark flag
- Primary matched system
- Illiopolis
- Source water
- Groundwater
- County
- Sangamon 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
0.0042 mg/L
28% of action level
Utility match
2 systems
Serves 1,037 people system-wide
Hardness meter
How hard is the water?
Estimated local hardness
USGS hardness classification scale
309 PPM
Soft
0–59Moderate
60–120Hard
121–180Very hard
181+
0–59Moderate
60–120Hard
121–180Very hard
181+
Parts per million
309
mg/L as CaCO₃ equivalent
Grains per gallon
18.1
1 GPG ≈ 17.1 PPM
What this means at home
At 309 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
31
Nearest site
20.3 mi
Observation range
May 22, 2017–Jul 30, 2025
Estimate confidence
Moderate
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: 18N 3E-18.6a (Well).USGS source documentation ↗
Regional context
Is 62539 typical?
These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.
Illiopolis median
309 PPM
About the same1 indexed ZIP readings · Range 309–309 PPM
Illinois median
285 PPM
24 PPM higher1065 indexed ZIP readings · Range 115–408 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)
0.0042 mg/L
Reported Dec 31, 2025
Copper (CU90)
Not available
No numerical 90th-percentile result
Numerical coverage
2 comparable results
Missing values remain blank; absence is not treated as a pass.
Lead (90th percentile)
Measured in mg/L
Local 0.0042
EPA limit 0.015
TTHM
Measured in MG/L
Local 0.092
EPA limit 0.08
Share of EPA benchmark
100% line = listed limit
2026Q2
- All records
- 12
- Health-based
- 4
- Active health-based
- 0
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| TTHM | IL1670550 | Resolved | Apr 1, 2025through Jun 30, 2025 |
| Total Haloacetic Acids (HAA5) | IL1670550 | Resolved | Apr 1, 2025through Jun 30, 2025 |
| Lead and Copper Rule | IL1670260 | Resolved | Apr 1, 2025through Aug 7, 2025 |
| TTHM | IL1670550 | Resolved | Jul 1, 2024through Sep 30, 2024 |
| Lead and Copper Rule | IL1670550 | Resolved | Oct 1, 2023through Mar 7, 2024 |
| Consumer Confidence Rule | IL1670550 | Resolved | Jul 1, 2023through Apr 10, 2024 |
| Combined Radium (-226 and -228) | IL1670260 | Resolved | Jan 1, 2023through Mar 31, 2023 |
| Combined Radium (-226 and -228) | IL1670260 | Resolved | Oct 1, 2022through Dec 31, 2022 |
| TTHMHealth-basedReported 0.092 MG/L · MCL 0.08 | IL1670550 | Resolved | Apr 1, 2022through Jun 30, 2022 |
| TTHMHealth-basedReported 0.091 MG/L · MCL 0.08 | IL1670550 | Resolved | Jan 1, 2022through Mar 31, 2022 |
| TTHMHealth-basedReported 0.093 MG/L · MCL 0.08 | IL1670550 | Resolved | Oct 1, 2021through Dec 31, 2021 |
| TTHMHealth-basedReported 0.084 MG/L · MCL 0.08 | IL1670550 | Resolved | Jul 1, 2021through Sep 30, 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 Illiopolis ZIP 62539 using 309 PPM nearby hardness and 2 reported measurement benchmarks.
Scale protection
High-Capacity Whole House Water Softener
309 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
TTHM 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 Illiopolis
Is tap water safe in Illiopolis?+
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 309 PPM, or 18.1 grains per gallon, classified as very hard. This is not a household tap measurement.
Do I need a water softener?+
At 309 PPM, a correctly sized whole-house softener can reduce scale and hard-water spotting. It does not replace contaminant filtration.