Water hardness in Kokomo
21.2 gpg very hard
Tap water in Kokomo is very hard: 21.2 gpg (363 mg/L · 20.3 °dH · 36.3 °fH).
Source: Indiana American Water, water quality report (Kokomo) (2025) · data checked 2026-10-20
Range across supply zones: 240–520 mg/L.
Indiana American Water treats Wildcat Creek surface water in Kokomo and adds groundwater from wells. Surface water and groundwater differ, so the range is 240–520 mg/L around 363 mg/L CaCO₃. Central Indiana's limestone-rich glacial deposits make this very hard water, with heavy scale on heaters.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 21.2 gpg |
|---|---|
| Utility | Indiana American Water |
How Kokomo compares
- Tap water in Kokomo is 134 % harder than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 105 of 1372 in the United States (1 = hardest); 92 % of these cities have softer water.
- In Indiana it is number 13 of 40 cities; the regional median is 20 gpg.
- Nearest city with clearly softer water: Sheridan, 38 km away (16.3 gpg).
- Nearest city with clearly harder water: Noblesville, 49 km away (27.3 gpg).
Ranking of the hardest and softest water in the United States →
What it means at home
- Severe scale: heater elements and washing-machine heaters fail early.
- Detergent use is very high; taps and screens coat within days.
- Dishwasher at maximum salt setting.
- An ion-exchange softener is practically essential; RO for drinking water.
How much salt will you use for softening?
Yes. At this hardness a softener pays for itself through appliance life and detergent.
Descale a coffee machine or kettle about every 1 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Kokomo
| Brand | Setting for this water |
|---|---|
| Bosch | H05 |
| Miele | 20 °dH |
| AEG / Electrolux | 5 |
| Beko | 6th |
| Hoover | S3 |
| LG | H3 |
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 Kokomo water hard or soft?
It is very hard: 363 mg/L as CaCO₃ (21.2 gpg, 20.3 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Kokomo 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 Kokomo water?
21.2 gpg, equal to 20.3 °dH, 36.3 °fH or 363 mg/L calcium carbonate.
What dishwasher salt setting should I use in Kokomo?
For 363 mg/L (20.3 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Kokomo?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Indiana American Water, water quality report (Kokomo) (2025). Method: figure published by the water supplier. Indiana American Water, water quality report (Kokomo) · Outdated figure? Tell us