Water hardness in Los Angeles
7.5 gpg hard
Tap water in Los Angeles is hard: 7.5 gpg (128 mg/L · 7.2 °dH · 12.8 °fH).
Source: LADWP 2025 Drinking Water Quality Report (2025) · data checked 2026-10-19
Range across supply zones: 78–280 mg/L.
6 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| gpg | mg/L | ||
|---|---|---|---|
| Los Angeles Aqueduct Filtration Plant | 6 | 103 | moderately hard |
| MWD Diemer Plant | 13.8 | 236 | very hard |
| MWD Jensen Plant | 8.2 | 140 | hard |
| MWD Weymouth Plant | 13.7 | 234 | very hard |
| Northern Combined Wells | 6.7 | 115 | moderately hard |
| Southern Combined Wells | 6.8 | 116 | moderately hard |
LADWP serves water from several supplies, and hardness depends on the neighborhood. Its 2025 report lists the Los Angeles Aqueduct Filtration Plant at 103 mg/L and the groundwater wells at 115 and 116 mg/L. Purchased Metropolitan Water District supply is harder at the Weymouth and Diemer plants (234 and 236 mg/L) and 140 mg/L at Jensen. The citywide figure of 128 mg/L (7.5 gpg) is a median across these supplies, so check which one reaches your address.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 7.5 gpg |
|---|---|
| Utility | Los Angeles Department of Water and Power (LADWP) |
How Los Angeles compares
- Tap water in Los Angeles is 17 % softer than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 849 of 1372 in the United States (1 = hardest); 38 % of these cities have softer water.
- In California it is number 219 of 336 cities; the regional median is 9.5 gpg.
- Nearest city with clearly softer water: San Gabriel, 14 km away (5.8 gpg).
- Nearest city with clearly harder water: Huntington Park, 8 km away (13.1 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 Los Angeles
| Brand | Setting for this water |
|---|---|
| Bosch | H01 |
| Miele | 7 °dH |
| AEG / Electrolux | 2 |
| Beko | 2nd |
| Hoover | S1 |
| 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 Los Angeles water hard or soft?
It is hard: 128 mg/L as CaCO₃ (7.5 gpg, 7.2 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Los Angeles 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 Los Angeles water?
7.5 gpg, equal to 7.2 °dH, 12.8 °fH or 128 mg/L calcium carbonate.
What dishwasher salt setting should I use in Los Angeles?
For 128 mg/L (7.2 °dH) check your manufacturer's table: level 4–5.
Do I need a water softener in Los Angeles?
Recommended if you have a water heater, boiler or tankless unit: it saves repairs and detergent.
Source
Source: LADWP 2025 Drinking Water Quality Report (2025). Method: figure published by the water supplier. LADWP 2025 Drinking Water Quality Report · Outdated figure? Tell us