Water hardness in St. John
28 gpg very hard
Tap water in St. John is very hard: 28 gpg (479 mg/L · 26.9 °dH · 47.9 °fH).
Source: Town of St. John 2025 Water Quality Report (2025) · data checked 2026-11-02
Range across supply zones: 445–514 mg/L.
The Town of St. John Water Department reports 479.4 mg/L on average in its 2025 water quality report, within a range of 445.1 to 513.6 mg/L. That is very hard water, and the value is computed from the published figures. The report is the only source used here, so we say nothing about where the supply comes from. Expect heavy scale on kettles and water heaters.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 28 gpg |
|---|---|
| Utility | Town of St. John Water Department |
How St. John compares
- Tap water in St. John is 209 % harder than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 17 of 1372 in the United States (1 = hardest); 99 % of these cities have softer water.
- In Indiana it is number 1 of 40 cities; the regional median is 20 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 St. John
| Brand | Setting for this water |
|---|---|
| Bosch | H06 |
| Miele | 27 °dH |
| AEG / Electrolux | 6 |
| Beko | 6th |
| Hoover | S4 |
| LG | H4 |
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 St. John water hard or soft?
It is very hard: 479 mg/L as CaCO₃ (28 gpg, 26.9 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in St. John 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 St. John water?
28 gpg, equal to 26.9 °dH, 47.9 °fH or 479 mg/L calcium carbonate.
What dishwasher salt setting should I use in St. John?
For 479 mg/L (26.9 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in St. John?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Town of St. John 2025 Water Quality Report (2025). Method: computed from supplier's calcium and magnesium. Town of St. John 2025 Water Quality Report · Outdated figure? Tell us