Does it require cleaning or other maintenance?

The QB-21 has no planned maintence at all. Its is essentially a smooth bore copper pipe which replaces a smooth bore plastic pipe for a 2.1m length.

Will it work with dishwashers or washing machines?

No, not really in a domestic situation. However this can de done in commercial situations where many appliances are filling and discharging all day, especially if a buffer tank is employed to balance out the water flows.