a method and corresponding apparatus employ purified water to backflush a filtration device . purified water includes water having a total dissolved solids reading less than that of the water being filtered . examples of purified water may include water treated using reverse osmosis , steam distillation , or deionization processes , and the like . in the simplest form , the purified water is used to rinse or backflush a filter or filter cartridge . further extensions include valves to switch from a primary flowpath used for normal operations to a secondary flowpath used to conduct backflushing routines . backflushing routines may be initiated on demand or through an automated routine that repeats the process on a regular basis .