DeKalb Water Hardness & Quality Report (2026)
Water Hardness
7.9 grains per gallon
Source
river
pH Level
7.8
neutral = 7.0
Lead
0.003 mg/L
✓ Below action level
TDS
235.9 mg/L
Est. Daily Cost
$0.36
energy & soap waste
Source: USGS Water Quality Portal · Updated 2026
0–60
mg/L
Soft
61–120
mg/L
Moderately Hard
121–180
mg/L
Hard
180+
mg/L
Very Hard
Appliance Damage Report
In DeKalb, your appliances are currently losing 18% efficiency due to mineral buildup.
| Appliance | In DeKalb | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 5.1 yrs | 8.5 yrs | -40% |
| Washing Machine | 8.6 yrs | 12 yrs | -28% |
| Water Heater | 10.2 yrs | 15 yrs | -32% |
Regional Water Comparison
How DeKalb compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ DeKalb, Illinois | 136 mg/L | 4.9 ppt | 🟠 Hard | river |
| Sycamore, Illinois | 160 mg/L | 5.7 ppt | 🟠 Hard | river |
| Wasco, Illinois | 149 mg/L | 5.3 ppt | 🟠 Hard | river |
| Belvidere, Illinois | 140.5 mg/L | 5 ppt | 🟠 Hard | river |
| Village of Campton Hills, Illinois | 165.5 mg/L | 5.9 ppt | 🟠 Hard | river |
National Benchmark
How DeKalb compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ DeKalb | 136 mg/L | 🟠 Moderate |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes DeKalb's Water Unique?
Local geology and source profile
DeKalb, Illinois, in DeKalb County west of Chicago — home of Northern Illinois University (NIU Huskies, a major Illinois state university), the 'Barb City' (named for the invention of barbed wire — Joseph Glidden invented modern barbed wire in DeKalb in 1874, one of the most transformative inventions in American agricultural history), and a major northern Illinois agricultural college and manufacturing community in the northern Illinois cornbelt — draws its municipal water supply from the Ironton–Galesville Sandstone Aquifer via the City of DeKalb Water Division. Water hardness in DeKalb measures 136 mg/L — classified as moderately hard.
DeKalb's moderate hardness reflects the DeKalb County deep sandstone aquifer and calcareous glacial terrain. The Ironton–Galesville Sandstone (a deep Cambrian-age sandstone aquifer in northern Illinois) provides DeKalb's primary water supply, drawing from calcareous sandstone aquifer confined beneath calcareous glacial till. DeKalb County sits on Wisconsin Age calcareous glacial till from the Lake Michigan Lobe (calcareous till from the Michigan Basin dolomite terrain). The deep Cambrian sandstone aquifer, recharged through the calcareous Illinois Paleozoic sequence, produces the moderate 136 mg/L at DeKalb.
At 136 mg/L, DeKalb residents encounter moderate-to-hard scale accumulation. Monthly cleaning with citric acid solution is recommended for faucet aerators and showerheads. City of DeKalb Water Division consistently delivers water meeting all Illinois EPA and federal EPA Safe Drinking Water Act requirements.
Geology & Source: Groundwater from the Ironton–Galesville Sandstone Aquifer via the City of DeKalb Water Division — the DeKalb County north-central Illinois calcareous glacial outwash (Wisconsin Age Lake Michigan Lobe calcareous till and Cambrian–Ordovician calcareous sandstone aquifer); moderately hard supply at 136 mg/L in DeKalb County.