My first post, so please bare with me. Is there a good way to track the direction of a drain line running into the basement floor cement slab? I'm looking to add a bathroom 'not' where one was roughed in. I have clear visibility of the drain and vent lines going into the cement floor that are very close to where I would like to tap into. Hopefully it is as easy as knowing where the lines are and then cutting/jackhammering into the floor. Any advice would be greatly appreciated.