ender is correct, we have deluded ourselves about how much control we have over the most adapted life form in our tanks. Non issue using tap water to clean filters.
we can link some studies showing nitrifying bacteria living in, and coming out of the tap. in fact it varies and at times can be surprisingly high, see the colony count averages from your local tap supplier. They are a small portion of mixed aerobic colonies found in all post treated tap everywhere.
so to be accurate, using tap can seed your filter
the chlorine is a reducer in ideal conditions in clean, non accumulated piping which is never the case on the other end and certainly in our tanks. Your local water report w show lots of living bacterial colonies coming right out of the tap, the chlorine has only a partial effect in ideal conditions.
there are scums and biofilms that insulate much of the intact, adhered colonies while we squeeze off some mulm
sure, some will be killed, just not enough to matter. Anyone who works with bacteria for a living knows they are tough in our tanks
blasting your filter mass with peroxide and no water won't even make a notable dent, aerobes aren't particularly flummoxed by some elevated oxygen. Those that were killed or dislodged are back to norm mass in 20 hours so my vote is rinse in tap if you want, or the purest ro. One way simply feels better than the other, but in the end surgeons use much more than a tap water rinse to sterilize those forearms for the scrub in
we can clean our filters as often as we like and doing so maintains surface area vs clogged up channels... exporting the mulm that collects in them cant be done often enough. All they need to be able to oxidize ammonia is a thin biofilm layer of bacterial community adhered to filter micro surfaces and semi oxygenated water flowing past. Rinsing out filters won't remove that element and it does remove pockets of partially degraded waste which is adding to the bioload the filter is trying to support.