Water Harvesting Systems
Rain to mains or water harvesting are some of the names for integrating tank water supply and the mains supply system with a view to saving on water.
Typically these systems are used for laundries and toilets, reserving the mains for drinking and showering.
There are a range of systems including Waterpro Rains to Mains Controller, Davey Rainbank, Onga Waterswitch, Grundfos Aquasaver, and others.