Water hardness in Hermosa Beach
29.3 gpg very hard
Tap water in Hermosa Beach is very hard: 29.3 gpg (502 mg/L · 28.1 °dH · 50.2 °fH).
Source: Cal Water 2025 Water Quality Report, Hermosa-Redondo (2025) · data checked 2026-10-29
Range across supply zones: 486–517 mg/L.
Hermosa Beach is served by California Water Service through its Hermosa-Redondo system. The 2025 report gives a median hardness of 502 mg/L, with a range of 486 to 517 mg/L. This is among the hardest water in our data. Expect fast scale on heaters, fixtures and glass.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 29.3 gpg |
|---|---|
| Calcium (mg/L) | 141 |
| Magnesium (mg/L) | 37 |
| Utility | California Water Service (Hermosa-Redondo system) |
How Hermosa Beach compares
- Tap water in Hermosa Beach is 224 % harder than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 11 of 1372 in the United States (1 = hardest); 99 % of these cities have softer water.
- In California it is number 5 of 336 cities; the regional median is 9.5 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 Hermosa Beach
| Brand | Setting for this water |
|---|---|
| Bosch | H06 |
| Miele | 28 °dH |
| AEG / Electrolux | 6 |
| Beko | 6th |
| Hoover | S4 |
| LG | H4 |
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 Hermosa Beach water hard or soft?
It is very hard: 502 mg/L as CaCO₃ (29.3 gpg, 28.1 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Hermosa Beach 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 Hermosa Beach water?
29.3 gpg, equal to 28.1 °dH, 50.2 °fH or 502 mg/L calcium carbonate.
What dishwasher salt setting should I use in Hermosa Beach?
For 502 mg/L (28.1 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Hermosa Beach?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Cal Water 2025 Water Quality Report, Hermosa-Redondo (2025). Method: figure published by the water supplier. Cal Water 2025 Water Quality Report, Hermosa-Redondo · Outdated figure? Tell us