I'm moving a kitchen around and therefore need to route waste for washing maching/ dishwasher and sink. After drillijng a hole in the wall I have several options. I have a soil pipe close by, and down pipe from gutter and I could reach the old "old open drain" from the old waste. What do regulations allow me to pump into?
I would guess that the downpipe from the gutters and the open grate that you talk about are connected to the surface water sewers. The regulations stop you putting any fowl water into that. Fowl water is basically anything that comes out of the house, toilet, sinks, showers, washing m/c etc etc.