Hardness
Very Hard
320 PPM · 18.7 GPG
Local water dashboard
Official source aggregationWater quality in Joliet, IL 60435
A source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for Will County.
1 active health-based violation
- Primary matched system
- Joliet
- Source water
- Groundwater + Surface water
- County
- Will County
- Profile updated
At a glance
What the current records say
EPA quarter 2026Q2
Compliance screen
Review needed
1 active health-based record
Lead 90th percentile
0.0065 mg/L
43% of action level
Utility match
10 systems
Serves 160,000 people system-wide
Hardness meter
How hard is the water?
Estimated local hardness
USGS hardness classification scale
320 PPM
Soft
0–59Moderate
60–120Hard
121–180Very hard
181+
0–59Moderate
60–120Hard
121–180Very hard
181+
Parts per million
320
mg/L as CaCO₃ equivalent
Grains per gallon
18.7
1 GPG ≈ 17.1 PPM
What this means at home
At 320 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
108
Nearest site
8.9 mi
Observation range
May 30, 2017–May 13, 2026
Estimate confidence
Moderate
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: 34N 9E- 8.8h1 (Well).USGS source documentation ↗
Regional context
Is 60435 typical?
These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.
Joliet median
320 PPM
About the same6 indexed ZIP readings · Range 320–320.5 PPM
Illinois median
285 PPM
35 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)
0.0065 mg/L
Reported Jun 30, 2026
Copper (CU90)
2.14 mg/L
Reported Dec 31, 2025
Numerical coverage
2 comparable results
Missing values remain blank; absence is not treated as a pass.
Lead (90th percentile)
Measured in mg/L
Local 0.0065
EPA limit 0.015
Copper (90th percentile)
Measured in mg/L
Local 2.14
EPA limit 1.3
Share of EPA benchmark
100% line = listed limit
2026Q2
- All records
- 703
- Health-based
- 4
- Active health-based
- 1
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| Chlorine | IL1977730 | Archived | Mar 1, 2026through Mar 31, 2026 |
| Revised Total Coliform Rule | IL1977730 | Archived | Mar 1, 2026through Mar 31, 2026 |
| Revised Total Coliform Rule | IL1975105 | Archived | Mar 1, 2026through Mar 31, 2026 |
| Chlorine | IL1975105 | Archived | Mar 1, 2026through Mar 31, 2026 |
| Public Notice | IL1975105 | Unaddressed | Jan 14, 2026 |
| Public Notice | IL1975105 | Unaddressed | Jan 14, 2026 |
| Public Notice | IL1975105 | Unaddressed | Jan 14, 2026 |
| Public Notice | IL1975105 | Unaddressed | Jan 14, 2026 |
| Chlorine | IL1977490 | Resolved | Jan 1, 2026through Jan 31, 2026 |
| Revised Total Coliform Rule | IL1977490 | Resolved | Jan 1, 2026through Jan 31, 2026 |
| 1,2-Dichloropropane | IL1975105 | Archived | Jan 1, 2026through Mar 31, 2026 |
| Picloram | IL1975105 | Archived | Jan 1, 2026through Mar 31, 2026 |
| Pentachlorophenol | IL1975105 | Archived | Jan 1, 2026through Mar 31, 2026 |
| LASSO | IL1975105 | Archived | Jan 1, 2026through Mar 31, 2026 |
| 2,4,5-TP | IL1975105 | Archived | Jan 1, 2026through Mar 31, 2026 |
| Dinoseb | IL1975105 | Archived | Jan 1, 2026through Mar 31, 2026 |
| Chlordane | IL1975105 | Archived | Jan 1, 2026through Mar 31, 2026 |
| Diquat | IL1975105 | Archived | Jan 1, 2026through Mar 31, 2026 |
| Trichloroethylene | IL1975105 | Archived | Jan 1, 2026through Mar 31, 2026 |
| Di(2-ethylhexyl) adipate | IL1975105 | Archived | Jan 1, 2026through Mar 31, 2026 |
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 Joliet ZIP 60435 using 320 PPM nearby hardness and 2 reported measurement benchmarks.
Scale protection
High-Capacity Whole House Water Softener
320 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
Copper (90th percentile) 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.
Nearby indexed reports
Compare ZIPs in Joliet
Estimates can differ across a city because monitoring locations and associated systems differ.
Frequently asked
Water questions for Joliet
Is tap water safe in Joliet?+
EPA ECHO reports 1 active health-based violation among the associated community water systems. Review the affected utility's current notice and Consumer Confidence Report.
How hard is the water?+
Nearby USGS observations produce an estimate of 320 PPM, or 18.7 grains per gallon, classified as very hard. This is not a household tap measurement.
Do I need a water softener?+
At 320 PPM, a correctly sized whole-house softener can reduce scale and hard-water spotting. It does not replace contaminant filtration.