Water hardness in Coeur d'Alene
8.2 gpg hard
Tap water in Coeur d'Alene is hard: 8.2 gpg (141 mg/L · 7.9 °dH · 14.1 °fH).
Source: City of Coeur d'Alene Water Department, 2025 Water Quality Report (CCR) (2025) · data checked 2026-10-23
Range across supply zones: 136–146 mg/L.
Coeur d'Alene gets all of its water from wells in the Rathdrum Prairie aquifer, a sole-source aquifer of coarse glacial gravel, having previously drawn from the lake. Hardness is 141.2 mg/L CaCO₃ (135.6–146.2 mg/L), which is hard. Expect scale on glass and heaters.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 8.2 gpg |
|---|---|
| Utility | City of Coeur d'Alene Water Department |
How Coeur d'Alene compares
- Tap water in Coeur d'Alene is 9 % softer than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 759 of 1372 in the United States (1 = hardest); 45 % of these cities have softer water.
- In Idaho it is number 6 of 9 cities; the regional median is 9.4 gpg.
- Nearest city with clearly softer water: Lewiston, 144 km away (2.1 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 Coeur d'Alene
| Brand | Setting for this water |
|---|---|
| Bosch | H01 |
| Miele | 8 °dH |
| AEG / Electrolux | 2 |
| Beko | 3rd |
| Hoover | S1 |
| LG | H2 |
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 Coeur d'Alene water hard or soft?
It is hard: 141 mg/L as CaCO₃ (8.2 gpg, 7.9 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Coeur d'Alene 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 Coeur d'Alene water?
8.2 gpg, equal to 7.9 °dH, 14.1 °fH or 141 mg/L calcium carbonate.
What dishwasher salt setting should I use in Coeur d'Alene?
For 141 mg/L (7.9 °dH) check your manufacturer's table: level 4–5.
Do I need a water softener in Coeur d'Alene?
Recommended if you have a water heater, boiler or tankless unit: it saves repairs and detergent.
Source
Source: City of Coeur d'Alene Water Department, 2025 Water Quality Report (CCR) (2025). Method: figure published by the water supplier. City of Coeur d'Alene Water Department, 2025 Water Quality Report (CCR) · Outdated figure? Tell us