Water hardness in Gahanna
7 gpg hard
Tap water in Gahanna is hard: 7 gpg (120 mg/L · 6.7 °dH · 12 °fH).
Source: City of Columbus Division of Water - Water Hardness (2026) · data checked 2026-11-02
Gahanna is supplied by the City of Columbus Division of Water from its Hap Cremean plant, which lists hardness of about 120 mg/L as CaCO3. That is in the hard category. The figure comes from the supplier, so individual taps may read slightly differently.
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 Columbus Division of Water (Hap Cremean plant, supplier to Gahanna) |
How Gahanna compares
- Tap water in Gahanna is 23 % softer than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 884 of 1372 in the United States (1 = hardest); 34 % of these cities have softer water.
- In Ohio it is number 10 of 31 cities; the regional median is 7 gpg.
Ranking of the hardest and softest water in the United States →
What it means at home
- Fast scale on taps, shower screens and kettle; white spots on glassware.
- Water heater: efficiency loss and element failures within years if unprotected.
- Dry skin and dull hair after showering are common.
- Softener recommended; jug or reverse osmosis for drinking.
How much salt will you use for softening?
Recommended, especially with a heater or boiler: scale cuts efficiency and shortens its life.
Descale a coffee machine or kettle about every 2 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Gahanna
| 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 Gahanna water hard or soft?
It is 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 Gahanna 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 Gahanna water?
7 gpg, equal to 6.7 °dH, 12 °fH or 120 mg/L calcium carbonate.
What dishwasher salt setting should I use in Gahanna?
For 120 mg/L (6.7 °dH) check your manufacturer's table: level 4–5.
Do I need a water softener in Gahanna?
Recommended if you have a water heater, boiler or tankless unit: it saves repairs and detergent.
Source
Source: City of Columbus Division of Water - Water Hardness (2026). Method: figure published by the water supplier. City of Columbus Division of Water - Water Hardness · Outdated figure? Tell us