Water hardness in Barstow
15.8 gpg very hard
Tap water in Barstow is very hard: 15.8 gpg (270 mg/L · 15.1 °dH · 27 °fH).
Source: California SWRCB Division of Drinking Water, EDT lab results, system CA3610043 (2026-02) · data checked 2026-10-19
Range across supply zones: 212–320 mg/L.
The figure is for Golden State Water Company in Barstow, from State Water Resources Control Board lab results. The median of 33 results from 2023 to 2026, taken at 16 well points, is 270 mg/L as CaCO3 (15.8 gpg), with a range of 212 to 320 mg/L. This is very hard water. Scale builds quickly on heaters and fixtures.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 15.8 gpg |
|---|---|
| Utility | Golden State Water Co - Barstow |
How Barstow compares
- Tap water in Barstow is 74 % harder than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 326 of 1372 in the United States (1 = hardest); 76 % of these cities have softer water.
- In California it is number 57 of 336 cities; the regional median is 9.5 gpg.
- Nearest city with clearly softer water: Apple Valley, 43 km away (8.1 gpg).
- Nearest city with clearly harder water: Glendale, 134 km away (21 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 Barstow
| Brand | Setting for this water |
|---|---|
| Bosch | H04 |
| Miele | 15 °dH |
| AEG / Electrolux | 4 |
| 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 Barstow water hard or soft?
It is very hard: 270 mg/L as CaCO₃ (15.8 gpg, 15.1 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Barstow 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 Barstow water?
15.8 gpg, equal to 15.1 °dH, 27 °fH or 270 mg/L calcium carbonate.
What dishwasher salt setting should I use in Barstow?
For 270 mg/L (15.1 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Barstow?
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 CA3610043 (2026-02). Method: own measurement. California SWRCB Division of Drinking Water, EDT lab results, system CA3610043 · Outdated figure? Tell us