Water Softener Salt: Pellets vs. Crystals vs. Rock
Which salt type is best for your water softener and why it matters.
Three types of softener salt
Evaporated salt pellets: Purest form (99.9% sodium chloride). Dissolves cleanly, minimal residue, least maintenance. Most expensive ($6-8 per 40 lb bag). Recommended by most softener manufacturers. Solar salt crystals: Made by evaporating seawater (99.6% pure). Slightly more residue than pellets. Moderate cost ($5-7). Good for most systems. Rock salt: Mined mineral salt (95-98% pure). Cheapest ($4-5) but contains insoluble minerals that build up as sludge in the brine tank, requiring more frequent cleaning.
Potassium chloride alternative
For those avoiding sodium, potassium chloride (KCl) works in standard softeners. It costs 2-3x more ($20-25 per 40 lb bag) and is slightly less efficient (requires 10-15% more salt per regeneration). The softened water contains potassium instead of sodium, which some prefer for health or environmental reasons.
How much you will use
Average household: one 40 lb bag per month. Higher hardness or larger households use more. Annual cost: $60-96 for evaporated pellets, $240-300 for potassium chloride.