Hi Randy you might want to try what I did when I was trying to locate what drains fed into a pipe that discharged directly into the woods behind my house. I went into the kitchen and relocated my wife's food coloring into my possession! Then I dumped the bottle of red down the toilet and the other colers in different drains. I found that the pipe was hooked up to the kitchen and the washing machine. Just a thought but it worked for me.

Bob