Backwash (Filtration)
Backwash is a self-cleaning cycle in which water flows backward through a filter or softener media bed to lift out trapped dirt and flush it to drain.
During normal operation, water flows down through a bed of media and the media collects particles or exchanges ions. Over time that bed packs down and loads up with debris, which slows flow and reduces performance. A backwash cycle reverses the flow, sending water up through the bed fast enough to fluff and lift the media, dislodging the trapped sediment and carrying it out to the drain.
Many whole-house treatment units run backwash automatically on a schedule or by water use. Sediment and iron filters backwash to clear collected grit and restore flow, while a softener includes a backwash step within its larger salt regeneration. The cycle is why these systems need a drain connection and why they briefly send water down the drain rather than to the house.
Backwashing keeps a media bed working without anyone taking it apart, but it has a cost: each cycle uses water and, for a softener, salt. A unit stuck backwashing too often, or never backwashing at all, points to a fouled bed or a control-valve fault.
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- Reverse Osmosis (RO) : Reverse osmosis is a filtration method that forces water through a fine semipermeable membrane to strip out dissolved salts, minerals, and most contaminants, producing very pure drinking water.
- Hard Water / Grains Per Gallon : Hard water is water high in dissolved calcium and magnesium, measured in grains per gallon (gpg), where higher numbers mean more scale, more soap scum, and faster appliance wear.
- Salt Bridge : A salt bridge is a hard crust that forms across the salt in a softener’s brine tank, leaving an air gap below it so the salt no longer dissolves into the water and regeneration fails.