: Hello Ellen, my name is Robert. I am a liscensed Plumber. I would have to say you would be better off having the ejector pump discharge into the main bldg. drain as close to where it goes out of the bldg. as possible. That way you are not washing the waste/sewer past existing plumbing fixtures. Doing so could possibly result in traps being siphoned or blockage. However, you can put your bathroom anywhere you'd like in the basement. Just run your 2" drain as close to the end of the main line as possible. I plumb custom homes usually 5000 sq. ft. up to 17000 sq. ft. and install ejector pumps all the time. My inspector likes the idea of having the ejector line discharge into the main line within 5'-10' of exiting the bldg. Good Luck with your project.: We live in a split level home and all of our bathrooms are upstairs. We would like to put a bathroom downstairs but one was not roughed out when the house was built. I have researched enough to know that we will need an ejector pump but what we are trying to decide is the best location for the bathroom. Should we put it closest to the septic tank or underneath one of the existing bathrooms. Thanks for your help.
While I agree on the advantage of a close main line tie in, as a repair plumber I feel it is usually how to get the vent up through the floor and tied into the kitchen sink or bathroom vent that most influences location in a existing structure. LonnythePlumber