What is surface water drainage and what does a ground rainwater drainage system entail?
Answer above plus… In properties not on mains drainage the rain water was not taken to septic tanks etc as the amount of water would be too much for the tank, it would dilute the bacteria too much. So surface water is taken to soak aways, these need to be at least 20 feet from a house and normal have about a meter cube of rubble, creating air pockets. The rain is drained into this and it soaks into the surrounding ground. If you have a private surface water system described here, you can get a rebate from your water company of anout £30 per year.
