There’s two drainage, one inside for the furnace, the other one is outside connected to the washing machine pipeline (1- 1/2 size). Every time the washing machine is used the water overflows from the drainage inside.
Installed a gate valve to stop overflowing from the drainage inside. But the water overflows from the drainage outside. But most of the water goes to the main cleanup, only a little bit of water goes back up but then goes back down right away.
If I install a valve for the outside drainage will it fix the problem?
drain services Mississauga, ON