Water hardness in San Ramon
14.8 gpg very hard
Tap water in San Ramon is very hard: 14.8 gpg (253 mg/L · 14.2 °dH · 25.3 °fH).
Source: DSRSD 2025 Annual Water Quality Report (2025) · data checked 2026-10-20
Range across supply zones: 58–448 mg/L.
The Dublin San Ramon Services District's 2025 report gives a very wide district-wide range of 58 to 448 mg/L (3.4 to 26.2 gpg), depending on the blend of supplies. The 253 mg/L (14.8 gpg) on this page is the midpoint of that range, which is very hard. The district does not serve San Ramon alone, and the report does not split the figure by area. Find out what reaches your address before sizing a softener.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 14.8 gpg |
|---|---|
| Utility | Dublin San Ramon Services District (DSRSD) |
How San Ramon compares
- Tap water in San Ramon is 63 % harder than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 368 of 1372 in the United States (1 = hardest); 73 % of these cities have softer water.
- In California it is number 71 of 336 cities; the regional median is 9.5 gpg.
- Nearest city with clearly softer water: Walnut Creek, 16 km away (1.1 gpg).
- Nearest city with clearly harder water: Pleasanton, 15 km away (20.4 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 San Ramon
| Brand | Setting for this water |
|---|---|
| Bosch | H04 |
| Miele | 14 °dH |
| AEG / Electrolux | 3 |
| Beko | 4th |
| Hoover | S2 |
| LG | H3 |
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 San Ramon water hard or soft?
It is very hard: 253 mg/L as CaCO₃ (14.8 gpg, 14.2 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in San Ramon 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 San Ramon water?
14.8 gpg, equal to 14.2 °dH, 25.3 °fH or 253 mg/L calcium carbonate.
What dishwasher salt setting should I use in San Ramon?
For 253 mg/L (14.2 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in San Ramon?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: DSRSD 2025 Annual Water Quality Report (2025). Method: computed from supplier's calcium and magnesium. DSRSD 2025 Annual Water Quality Report · Outdated figure? Tell us