Water hardness in Fillmore
24.4 gpg very hard
Tap water in Fillmore is very hard: 24.4 gpg (418 mg/L · 23.4 °dH · 41.8 °fH).
Source: California SWRCB Division of Drinking Water, EDT lab results, system CA5610002 (2026-03) · data checked 2026-10-19
Range across supply zones: 321–644 mg/L.
The Fillmore figure comes from State Water Resources Control Board lab results for the Fillmore Water Department. It rests on 6 results from 2022 to 2026, taken at 3 well points: a median of 418 mg/L as CaCO3 (24.4 gpg), with a range of 320.5 to 643.5 mg/L. This is among the hardest water in our US set. Scale builds very fast.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 24.4 gpg |
|---|---|
| Utility | Fillmore Water Dept |
How Fillmore compares
- Tap water in Fillmore is 170 % harder than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 42 of 1372 in the United States (1 = hardest); 97 % of these cities have softer water.
- In California it is number 13 of 336 cities; the regional median is 9.5 gpg.
- Nearest city with clearly softer water: Moorpark, 13 km away (14.4 gpg).
- Nearest city with clearly harder water: Piru, 11 km away (37.8 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 Fillmore
| Brand | Setting for this water |
|---|---|
| Bosch | H06 |
| Miele | 23 °dH |
| AEG / Electrolux | 6 |
| Beko | 6th |
| Hoover | S3 |
| 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 Fillmore water hard or soft?
It is very hard: 418 mg/L as CaCO₃ (24.4 gpg, 23.4 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Fillmore 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 Fillmore water?
24.4 gpg, equal to 23.4 °dH, 41.8 °fH or 418 mg/L calcium carbonate.
What dishwasher salt setting should I use in Fillmore?
For 418 mg/L (23.4 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Fillmore?
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 CA5610002 (2026-03). Method: own measurement. California SWRCB Division of Drinking Water, EDT lab results, system CA5610002 · Outdated figure? Tell us