Water hardness in El Centro
20.2 gpg very hard
Tap water in El Centro is very hard: 20.2 gpg (345 mg/L · 19.3 °dH · 34.5 °fH).
Source: California SWRCB Division of Drinking Water, EDT lab results, system CA1310004 (2021-02) · data checked 2026-10-19
Range across supply zones: 340–350 mg/L.
This figure is over 3 years old; hardness may have changed.
The El Centro figure comes from State Water Resources Control Board lab results for the City of El Centro system. It rests on only 2 finished-water results, both from 2021: a median of 345 mg/L as CaCO3 (20.2 gpg), with a range of 340 to 350 mg/L. The data is old and thin. On this evidence the water is very hard, so check the city's current report.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 20.2 gpg |
|---|---|
| Utility | El Centro, City Of |
How El Centro compares
- Tap water in El Centro is 123 % harder than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 142 of 1372 in the United States (1 = hardest); 90 % of these cities have softer water.
- In California it is number 27 of 336 cities; the regional median is 9.5 gpg.
- Nearest city with clearly softer water: Coachella, 114 km away (3.2 gpg).
- Nearest city with clearly harder water: Blythe, 130 km away (36.8 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 El Centro
| Brand | Setting for this water |
|---|---|
| Bosch | H05 |
| Miele | 19 °dH |
| AEG / Electrolux | 5 |
| Beko | 5th |
| Hoover | S3 |
| 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 El Centro water hard or soft?
It is very hard: 345 mg/L as CaCO₃ (20.2 gpg, 19.3 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in El Centro 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 El Centro water?
20.2 gpg, equal to 19.3 °dH, 34.5 °fH or 345 mg/L calcium carbonate.
What dishwasher salt setting should I use in El Centro?
For 345 mg/L (19.3 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in El Centro?
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 CA1310004 (2021-02). Method: own measurement. California SWRCB Division of Drinking Water, EDT lab results, system CA1310004 · Outdated figure? Tell us