Here you go. Reward people with energy for these types of systems:

http://www.livingmachines.com/About-Living-Machine/Water-Reuse/Reuse-Explained.aspx

 Have a certain amount of energy given to those who reclaim water with this system. Reward a certain amount for every Liter/Gallon of water reclaimed and have that energycoin spendable on clean energy hardware like solar or wind.