Gray waters from the kitchen and showers are canalized in an open system of red clay which facilitates water aeration and exposure to UV sun rays to reduce microorganism load.

The water is then passed through a one cubic meter filter at the ground level, with different layers of stone, going from big to small from bottom to top. Sand is added at the bottom as well. The gray waters are used for land irrigation and toilets.

* Rain water is collected from the roof of the small house and stored in water tanks. This water is used for irrigation of the vegetable garden.