How-to

How to replace water softener resin

Buy the volume your tank holds, remove the valve, empty the old resin, refill around the riser and reinstall.

By Softenry Editorial · Updated October 2026

The short answer

Re-bed when hard water returns between regenerations even though the valve, settings and salt are fine. Buy the volume your tank holds: a cubic foot of standard resin is rated about 32,000 grains at full salt and about 24,000 at an efficient setting. Leave the free space above the bed the maker calls for; an overfilled tank can't backwash.

Steps

  • Bypass the softener, unplug it and relieve pressure.
  • Disconnect the plumbing and unscrew the control valve from the tank.
  • Hold the distributor (riser) tube in place and empty the old resin.
  • Cap the riser, add gravel underbed if your tank uses it, then pour in new resin.
  • Reinstall the valve, lubricating the riser seal; restore water slowly and run a manual regeneration.

How much to buy

Resin volume by grain rating (full salt)
RatingResin
24,0000.75 cu ft
32,0001 cu ft
48,0001.5 cu ft
64,0002 cu ft

Resin we cover: Purolite C100E 1 cu ft, AFWFilters SOFRES1 1 cu ft and DuraWater 10% crosslink resin.

Valve seals while you're there

With the valve off, it's the time to fit a rebuild kit such as the Fleck 60102-10. See all parts by valve in the lookup.

Safety

SafetyTanks are heavy when full. Use a helper, keep resin out of drains, and follow the valve maker's instructions.

Products mentioned

Questions readers ask

How much resin is in a 48,000-grain softener?
About 1.5 cubic feet; ratings run about 32,000 grains per cubic foot at full salt.
Do I need new gravel?
Only if your tank uses a gravel underbed and it's fouled; many residential tanks use a basket on the riser instead.