Water hardness in Daly City
10.7 gpg very hard
Tap water in Daly City is very hard: 10.7 gpg (184 mg/L · 10.3 °dH · 18.4 °fH).
Source: California SWRCB Division of Drinking Water, EDT lab results, system CA4110013 (2026-01) · data checked 2026-10-19
Range across supply zones: 144–311 mg/L.
The Daly City figure comes from State Water Resources Control Board lab results for the City of Daly City system. The median of 10 results from 2021 to 2026, taken at 5 well points, is 184 mg/L as CaCO3 (10.7 gpg), with a range of 143.8 to 311.4 mg/L. That is very hard on median, and the spread between wells is wide. Expect fast scale on heaters.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 10.7 gpg |
|---|---|
| Utility | City Of Daly City |
How Daly City compares
- Tap water in Daly City is 19 % harder than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 582 of 1372 in the United States (1 = hardest); 58 % of these cities have softer water.
- In California it is number 142 of 336 cities; the regional median is 9.5 gpg.
- Nearest city with clearly softer water: San Francisco, 9 km away (3.6 gpg).
- Nearest city with clearly harder water: San Ramon, 44 km away (14.8 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 Daly City
| Brand | Setting for this water |
|---|---|
| Bosch | H02 |
| Miele | 10 °dH |
| AEG / Electrolux | 2 |
| Beko | 3rd |
| Hoover | S2 |
| 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 Daly City water hard or soft?
It is very hard: 184 mg/L as CaCO₃ (10.7 gpg, 10.3 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Daly City 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 Daly City water?
10.7 gpg, equal to 10.3 °dH, 18.4 °fH or 184 mg/L calcium carbonate.
What dishwasher salt setting should I use in Daly City?
For 184 mg/L (10.3 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Daly City?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: California SWRCB Division of Drinking Water, EDT lab results, system CA4110013 (2026-01). Method: own measurement. California SWRCB Division of Drinking Water, EDT lab results, system CA4110013 · Outdated figure? Tell us