Have also been thinking about collecting all the water from the tumbledryer, which only goes down the drain and adds to the sewage water bill (we have to pay for water run-off - including rainwater run-off, for the upkeep of the drainage/sewage system). Since I use soap nuts to wash our clothes, with a tiny bit of lavender oil for a nice smell, there wouldn't be any harmful chemicals in the water, and I can use it for watering plants in the house, and those on the terrace in the summer.