In my previous flat, when I was hand washing some stuff in the bathroom sink, the foam was popping out thru the drain on the bathroom floor, when I was doing the washing up in the kitchen sink the water and foam would come up thru the drain on the kitchen floor. In my new flat (brand new place, rented thru a friend) the disgusting smell coming out of the drain on the kitchen floor makes me puke sometimes. I don't really see the point of having a desagüe on the kitchen floor!