Water hardness in DeKalb
7 gpg moderately hard
Tap water in DeKalb is moderately hard: 7 gpg (120 mg/L · 6.7 °dH · 12 °fH).
Source: City of DeKalb 2024 Water Quality Report (2024) · data checked 2026-11-02
DeKalb's water is supplied by the city's Water Division. The 2024 water quality report gives a hardness of 119.8 mg/L as CaCO3, in the moderate range. Light scale on heating elements and glass is typical. Check the latest report, as figures can shift from year to year.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 7 gpg |
|---|---|
| Utility | City of DeKalb Water Division |
How DeKalb compares
- Tap water in DeKalb is 23 % softer than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 903 of 1372 in the United States (1 = hardest); 34 % of these cities have softer water.
- In Illinois it is number 12 of 14 cities; the regional median is 8 gpg.
Ranking of the hardest and softest water in the United States →
What it means at home
- Visible kettle scale every few weeks; vinegar or citric acid is enough.
- Water heater and washing machine: some long-term scale; a scale inhibitor slows it.
- Dishwasher: medium salt setting.
- Softener optional; pays off mainly with a gas boiler or tankless heater.
How much salt will you use for softening?
Optional. A scale inhibitor or a small softener protects the heater; soap savings are modest.
Descale a coffee machine or kettle about every 3 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in DeKalb
| Brand | Setting for this water |
|---|---|
| Bosch | H01 |
| Miele | 7 °dH |
| AEG / Electrolux | 2 |
| Beko | 2nd |
| Hoover | S1 |
| LG | H1 |
From each brand's manual for the model family named in the source; your model may differ, so check its manual. All brands and how to change the setting →
FAQ
Is DeKalb water hard or soft?
It is moderately hard: 120 mg/L as CaCO₃ (7 gpg, 6.7 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in DeKalb safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
How many grains per gallon is DeKalb water?
7 gpg, equal to 6.7 °dH, 12 °fH or 120 mg/L calcium carbonate.
What dishwasher salt setting should I use in DeKalb?
For 120 mg/L (6.7 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in DeKalb?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: City of DeKalb 2024 Water Quality Report (2024). Method: figure published by the water supplier. City of DeKalb 2024 Water Quality Report · Outdated figure? Tell us