Water hardness in Cerritos
10.3 gpg hard
Tap water in Cerritos is hard: 10.3 gpg (176 mg/L · 9.8 °dH · 17.6 °fH).
Source: California SWRCB Division of Drinking Water, EDT lab results, system CA1910019 (2024-02) · data checked 2026-10-19
Range across supply zones: 165–217 mg/L.
The Cerritos figure comes from State Water Resources Control Board lab results for the city water department. It rests on 6 results from 2021 to 2024, taken at 3 well points: a median of 175.5 mg/L as CaCO3 (10.3 gpg), with a range of 165 to 216.5 mg/L. That is hard water, close to the very hard line. Expect visible scale on heaters.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 10.3 gpg |
|---|---|
| Utility | Cerritos - City, Water Dept. |
How Cerritos compares
- Tap water in Cerritos is 13 % harder than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 608 of 1372 in the United States (1 = hardest); 56 % of these cities have softer water.
- In California it is number 151 of 336 cities; the regional median is 9.5 gpg.
- Nearest city with clearly softer water: Signal Hill, 12 km away (6.7 gpg).
- Nearest city with clearly harder water: Norwalk, 5 km away (17.6 gpg).
Ranking of the hardest and softest water in the United States →
What it means at home
- Fast scale on taps, shower screens and kettle; white spots on glassware.
- Water heater: efficiency loss and element failures within years if unprotected.
- Dry skin and dull hair after showering are common.
- Softener recommended; jug or reverse osmosis for drinking.
How much salt will you use for softening?
Recommended, especially with a heater or boiler: scale cuts efficiency and shortens its life.
Descale a coffee machine or kettle about every 2 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Cerritos
| 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 Cerritos water hard or soft?
It is hard: 176 mg/L as CaCO₃ (10.3 gpg, 9.8 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Cerritos 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 Cerritos water?
10.3 gpg, equal to 9.8 °dH, 17.6 °fH or 176 mg/L calcium carbonate.
What dishwasher salt setting should I use in Cerritos?
For 176 mg/L (9.8 °dH) check your manufacturer's table: level 4–5.
Do I need a water softener in Cerritos?
Recommended if you have a water heater, boiler or tankless unit: it saves repairs and detergent.
Source
Source: California SWRCB Division of Drinking Water, EDT lab results, system CA1910019 (2024-02). Method: own measurement. California SWRCB Division of Drinking Water, EDT lab results, system CA1910019 · Outdated figure? Tell us