I can't argue with local ordinances. But I suspect most people trying to clean them with a garden hose going for a couple of hours would easily match back-washing in water use.

I don't have to back-wash much--I use the skimmer socks and a robotic cleaner that filters the as well as a DE filter (see the problems I had with my Dolphin).

It sounds like a plastic garbage can devoted to cartridge soaking is a great way to go--but I'm sticking with my sand filter. We have water restrictions due to several years of drought that were never lifted, but pool filters weren't affected.