Water hardness in Hollister
8.6 gpg hard
Tap water in Hollister is hard: 8.6 gpg (148 mg/L · 8.3 °dH · 14.8 °fH).
Source: California SWRCB Division of Drinking Water, EDT lab results, system CA3510001 (2025-09) · data checked 2026-10-19
Range across supply zones: 108–360 mg/L.
The Hollister figure comes from State Water Resources Control Board lab results for the City of Hollister system, using finished-water samples. The median of 46 results from 2023 to 2025 is 148 mg/L as CaCO3 (8.6 gpg), but results run from 107.5 to 359.5 mg/L. The water is hard on median and varies a lot. Confidence in the exact figure is moderate, so check the city's report.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 8.6 gpg |
|---|---|
| Utility | Hollister, City Of |
How Hollister compares
- Tap water in Hollister is 5 % softer than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 723 of 1372 in the United States (1 = hardest); 47 % of these cities have softer water.
- In California it is number 189 of 336 cities; the regional median is 9.5 gpg.
- Nearest city with clearly softer water: Milpitas, 78 km away (4.7 gpg).
- Nearest city with clearly harder water: Gilroy, 24 km away (13.8 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 Hollister
| Brand | Setting for this water |
|---|---|
| Bosch | H02 |
| Miele | 8 °dH |
| AEG / Electrolux | 2 |
| Beko | 3rd |
| 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 Hollister water hard or soft?
It is hard: 148 mg/L as CaCO₃ (8.6 gpg, 8.3 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Hollister 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 Hollister water?
8.6 gpg, equal to 8.3 °dH, 14.8 °fH or 148 mg/L calcium carbonate.
What dishwasher salt setting should I use in Hollister?
For 148 mg/L (8.3 °dH) check your manufacturer's table: level 4–5.
Do I need a water softener in Hollister?
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 CA3510001 (2025-09). Method: own measurement. California SWRCB Division of Drinking Water, EDT lab results, system CA3510001 · Outdated figure? Tell us