Was in Homebase tonight, and they sold 'Tees' (actually more of a through pipe with another one coming in as a side-entry) to plumb washing machine and dishwasher wastes together. Current arrangement is that my washing machine comes out in a flexi hose which then feeds into a vertical pipe that comes out of the ground. Presumably this tee fits onto this pipe and then the two wastes attach to it, but I am not sure exactly how. Do I sit this tee on the top of the existing pipe and then thread the w/m waste down through it, allowing the dishwasher water to run round the outside of the washign machine flexi, or do I have to cut the vertical pipe off near the bottom, add the tee and then fix both w/m and dishwasher flexis onto it ? Is there any danger of the w/m and dishwasher sending too much water down the pipe if they drain simultaneously ?