Well for WFP window washing, I like the Wash-it Pro and I know a lot of pros in the industry use it and recommend it, which is why I bought it.Do you guys know of any nice DI/RO systems?
As for carpet/tile cleaning, I can imagine a regular household setup could be used. The flow is slow so it would be something you would do overnight. I've thought about having something like that actually mounted above my fresh water tank so all I needed to do was connect a hose and turn on the water. I would probably have to set it up with a shutoff timer or a float valve to keep it from overflowing though.