Water hardness in Garden Grove
18.5 gpg very hard
Tap water in Garden Grove is very hard: 18.5 gpg (316 mg/L · 17.7 °dH · 31.6 °fH).
Source: California SWRCB Division of Drinking Water, EDT lab results, system CA3010062 (2026-05) · data checked 2026-10-19
Range across supply zones: 197–355 mg/L.
The Garden Grove figure comes from State Water Resources Control Board lab results for the City of Garden Grove system. The median of 27 results from 2022 to 2026 is 316 mg/L as CaCO3 (18.5 gpg), within a range of 196.6 to 354.8 mg/L. The sampling points are listed as wells. This is very hard water, and scale builds fast 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 | 18.5 gpg |
|---|---|
| Utility | City Of Garden Grove |
How Garden Grove compares
- Tap water in Garden Grove is 104 % harder than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 208 of 1372 in the United States (1 = hardest); 85 % of these cities have softer water.
- In California it is number 38 of 336 cities; the regional median is 9.5 gpg.
- Nearest city with clearly softer water: Westminster, 4 km away (14.4 gpg).
- Nearest city with clearly harder water: Torrance, 37 km away (26.8 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 Garden Grove
| Brand | Setting for this water |
|---|---|
| Bosch | H05 |
| Miele | 18 °dH |
| AEG / Electrolux | 4 |
| 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 Garden Grove water hard or soft?
It is very hard: 316 mg/L as CaCO₃ (18.5 gpg, 17.7 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Garden Grove 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 Garden Grove water?
18.5 gpg, equal to 17.7 °dH, 31.6 °fH or 316 mg/L calcium carbonate.
What dishwasher salt setting should I use in Garden Grove?
For 316 mg/L (17.7 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Garden Grove?
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 CA3010062 (2026-05). Method: own measurement. California SWRCB Division of Drinking Water, EDT lab results, system CA3010062 · Outdated figure? Tell us