Dear Robert, My mediteranian house has an underground, rainwater collection tank, filled by rain water. It is about 4m length x3m width x 2.5m height.The tank is siuated directly in front of the house, (SW-W). It used to supply the drinking water to the house. Now I wonder if I should keep it or fill it up, since I am connecting to the water mains. It was suggested to convert it into a sewage tank, since connection to the sewage mains is down the hillabout 30 m away from the house. I am not sure that converting it to a sewage pit is a good idea, I would not feel comfortable about having sewage pit in front of the house even if it is sealed underground. regards dragana vilinac