Backwash Interval
 

The time to wash is determined in one of several ways:

1. Some plants backwash the filters on a regular schedule at fixed periods of time.
   
2. Other plants backwash filters according to head loss as indicated by gauges.
   
3. A rise in turbidity may also call for backwashing.
   
4. Other reasons may include an installation of a new filter or an unexpected contamination.

A concern of either method is wasting of water and operational problems.