Water Softeners for Iron Removal

Does a water softener remove iron?

Yes — with limits. Ion-exchange resin captures dissolved (clear-water, ferrous) iron the same way it captures calcium and magnesium, so a properly sized softener will handle up to about 5 ppm of ferrous iron along with your hardness. Three conditions: the iron must be dissolved (water runs clear from the tap and stains later), you must oversize the softener for the extra load, and you must use a resin cleaner such as Iron Out or Res Care on a schedule, because iron that isn't fully rinsed off during regeneration fouls the resin bed over time.

When a softener alone isn't enough

If your water runs orange or red from the tap (oxidized, ferric iron), you have manganese or a rotten-egg (hydrogen sulfide) smell, or iron is above 5 ppm, the softener needs help. Put an air-injection (AIO), Katalox Light, Greensand Plus or Birm iron filter ahead of the softener — the filter takes out the iron and sulfur, the softener takes out the hardness, and the resin lasts for years instead of months. The order matters: iron filter first, softener second.

Sizing a softener for iron

Add 4–5 grains per gallon to your hardness for every 1 ppm of iron. A home with 15 gpg hardness and 3 ppm iron should be sized as roughly 30 gpg. Fine-mesh resin has more surface area and holds iron better than standard-mesh resin; 10% crosslink resin (an upgrade option on our Clack and Fleck builds) resists chlorine and iron oxidation damage.

Iron-rated systems — which one?

Water test in hand? Send us your report and we'll tell you whether a softener alone will do it. Also see Water Softeners for Well Water and Iron Filters.