“This instructable is a prototype to save or take advantage of the already used water (from washing machine and so …). How it works ? There are two water capacitive sensor; one of them is for sensing the WC water repository level, and the other one is for sensing the tank water level. Once the WC water repository is empty, the system has to check the tank level; if there is enough water to be pumped to the WC, a relay is turned on in order to start the water pumping; if there isn’t enough water in the tank, the system has to notify of that (in this case using a LED), and the relay is not turned on.”