Hardness
Very Hard
302 PPM · 17.7 GPG
Local water dashboard
Official source aggregationWater quality in Mark, IL 61340
A source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for Putnam County.
1 reported benchmark flag
- Primary matched system
- Mark
- Source water
- Groundwater
- County
- Putnam 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
1 system
Serves 555 people system-wide
Hardness meter
How hard is the water?
Estimated local hardness
USGS hardness classification scale
302 PPM
Soft
0–59Moderate
60–120Hard
121–180Very hard
181+
0–59Moderate
60–120Hard
121–180Very hard
181+
Parts per million
302
mg/L as CaCO₃ equivalent
Grains per gallon
17.7
1 GPG ≈ 17.1 PPM
What this means at home
At 302 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
29
Nearest site
13.8 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: 33N 2E- 9.7b1 (Well).USGS source documentation ↗
Regional context
Is 61340 typical?
These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.
Mark median
302 PPM
About the same1 indexed ZIP readings · Range 302–302 PPM
Illinois median
285 PPM
17 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 mg/L
Reported Jun 30, 2026
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
EPA limit 0.015
TTHM
Measured in MG/L
Local 0.098
EPA limit 0.08
Share of EPA benchmark
100% line = listed limit
2026Q2
- All records
- 4
- Health-based
- 1
- Active health-based
- 0
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| Lead and Copper Rule | IL1550250 | Unaddressed | Jan 1, 2026 |
| Lead and Copper Rule | IL1550250 | Resolved | Oct 1, 2022through Mar 7, 2024 |
| Public Notice | IL1550250 | Resolved | Jul 6, 2022through Jul 12, 2022 |
| TTHMHealth-basedReported 0.098 MG/L · MCL 0.08 | IL1550250 | Resolved | Apr 1, 2022through Jun 30, 2022 |
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 Mark ZIP 61340 using 302 PPM nearby hardness and 2 reported measurement benchmarks.
Scale protection
High-Capacity Whole House Water Softener
302 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 Mark
Is tap water safe in Mark?+
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 302 PPM, or 17.7 grains per gallon, classified as very hard. This is not a household tap measurement.
Do I need a water softener?+
At 302 PPM, a correctly sized whole-house softener can reduce scale and hard-water spotting. It does not replace contaminant filtration.