My builder has installed a 100 litre waterbutt in my garden. he used the package that came with the waterbutt to connect it to the downpipe. With the recent weather we have had it seems that when the waterbutt is full water the rest of the water is not diverting back to the downpipe but continues to leak from the waterbutt. is there anything else that can be used - as at present i have to empty out the waterbutt by chucking it down the drain just to stop all the water from eventually damaging my decking. surely this is not correct. when ive looked into the downpipe no water is flowing down. I assumed the package that caem with teh waterpipe would have had a diverter in or is it or is there something else that shoudl have been added. I hope someone can help me thanks