Re: Adding a Bathroom above a garage
As for the water supply lines this probably wouldn't be too much of an issue.... though there will likely be the need to open up ceilings , walls etc. .... depending on the layout.
The waste line is another story. In order to maintain the 1/4 inch per foot slope for a horizontal run probably wouldn't work.
It may very well be the waste line would travel vertically down an inside wall and connect up with the main waste pipe in the basement .... if you have one.
This is just a guess since it's impossible to tell over the internet what the conditions are.
Sounds like you will need to have a contractor come out and advise you onsite.
Just a thought.
"" an ounce of perception -- a pound of obscure "