I plan to install a new upstairs bathroom toilet, basin and bath. All three items will be on the same exterior wall. The basin is between the bath and the toilet.
If I connect the bath drain to the toilet soil drain pipe, outside just below the bath, a distance of about 8 foot, how much slope do I need?
Is it OK to connect the basin drain to the middle of the above pipe or should I have a separate connection to the soil pipe? The latter option would certainly prevent any water from the basin trying to enter the bath.