TL;DR
A backwash valve is the multiport or push-pull valve on a pool's sand or DE filter that reverses water flow through the filter bed, flushing trapped dirt out a waste line instead of returning it to the pool. The common multiport offers six positions, filter, backwash, rinse, waste, recirculate, closed, and the rinse step after backwashing resets the bed so debris does not blow back into the pool.
What it means
A backwash valve is the multiport or push-pull valve on a pool's sand or DE filter that reverses water flow through the filter bed, flushing trapped dirt out a waste line instead of returning it to the pool. The common multiport offers six positions, filter, backwash, rinse, waste, recirculate, closed, and the rinse step after backwashing resets the bed so debris does not blow back into the pool. The cycle is triggered when filter pressure climbs 8 to 10 psi over its clean baseline. Worn spider gaskets inside it are the usual cause of water trickling out the waste line continuously.
Where it sits in the glossary
Backwash valve is part of the Trade jargon group inside the ProFix Directory glossary. Browse every term in this category from the glossary index.
Why Ohio homeowners should know it
This is a term Ohio homeowners encounter when reading contractor quotes, hiring paperwork, or inspection reports. Understanding it well enough to ask one good follow-up question is usually all the protection a homeowner needs.
ProFix Directory keeps definitions short on the index page and saves the longer context — Ohio-specific rules, where the term comes from, and which ProFix tools touch it — for these per-term pages so the term is easy to cite and easy to share.
ProFix tools that touch this term
See also
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