How much salt does a softener use?
Annual salt, bags and cost, and what the dose setting changes.
Salt is the running cost of a softener, and it is almost entirely under your control. The same water, the same household and the same unit can use very different amounts of salt depending on one setting.
Annual salt at three settings
Four people, 15 grains per gallon, 300 gallons a day.
| Setting | Salt per regen | Days between | Salt per year | Bags | Cost at $8/bag |
|---|---|---|---|---|---|
| High efficiency, 6 lb/cu ft | 6.4 lb | 4.7 | 493 lb | 13 | $99 |
| Standard, 9 lb/cu ft | 9.6 lb | 5.7 | 614 lb | 16 | $123 |
| Maximum, 15 lb/cu ft | 16 lb | 7.1 | 816 lb | 21 | $163 |
The high-efficiency setting regenerates more often but uses less salt overall, because the resin gives up more grains per pound at a gentle dose. Most units ship on a middling default and most owners never change it.
What hard water costs before you soften it
Hardness precipitates out of water when it is heated, which is why the inside of a water heater is where scale collects. For the example household at 15 grains per gallon:
Not all of that deposits as scale, and how much does depends on temperature and water chemistry. The point is the order of magnitude: several pounds of mineral a year goes through a water heater in hard water, and the fraction that stays behind is what insulates the element and raises the bill.