Water hardness in Redmond
1.2 gpg soft
Tap water in Redmond is soft: 1.2 gpg (21 mg/L · 1.2 °dH · 2.1 °fH).
Source: Seattle Public Utilities Quarterly Surface Water Analysis 02/24/2026 (Tolt) (2026-02) · data checked 2026-10-23
Redmond's supply is the South Fork Tolt River supply from Seattle Public Utilities, delivered through the Cascade Water Alliance. Cascade snowmelt and rain carry very few minerals, so the water is soft at 20.9 mg/L CaCO₃. Scale is rare and a softener adds little.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 1.2 gpg |
|---|---|
| Calcium (mg/L) | 7.84 |
| Magnesium (mg/L) | 0.375 |
| Utility | City of Redmond (Tolt supply from Seattle Public Utilities via Cascade Water Alliance) |
How Redmond compares
- Tap water in Redmond is 87 % softer than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 1331 of 1372 in the United States (1 = hardest); 3 % of these cities have softer water.
- In Washington it is number 26 of 27 cities; the regional median is 2.8 gpg.
- Nearest city with clearly harder water: Seattle, 17 km away (1.5 gpg).
Ranking of the hardest and softest water in the United States →
What it means at home
- Little or no limescale in kettles, water heaters or washing machines.
- Soap lathers easily; water does not dry skin or hair.
- Dishwasher: salt setting at minimum or off.
- No softener needed; a jug filter only changes taste.
How much salt will you use for softening?
No. Water this soft does not need softening.
Descale a coffee machine or kettle about every 6 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Redmond
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 1 °dH |
| AEG / Electrolux | 1 |
| Beko | 1st |
| Hoover | S0 |
| LG | H0 |
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 Redmond water hard or soft?
It is soft: 21 mg/L as CaCO₃ (1.2 gpg, 1.2 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Redmond 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 Redmond water?
1.2 gpg, equal to 1.2 °dH, 2.1 °fH or 21 mg/L calcium carbonate.
What dishwasher salt setting should I use in Redmond?
For 21 mg/L (1.2 °dH) check your manufacturer's table: level 0–1, usually no salt.
Do I need a water softener in Redmond?
No. With soft water a softener adds nothing.
Source
Source: Seattle Public Utilities Quarterly Surface Water Analysis 02/24/2026 (Tolt) (2026-02). Method: figure published by the water supplier. Seattle Public Utilities Quarterly Surface Water Analysis 02/24/2026 (Tolt) · Outdated figure? Tell us