I am currently look at buying a home that has a detached garage with an empty room above the garage that could be converted into an apartment. My problem is, I want to put a bathroom into it and a small kitchen. I would need to run the plumbing to the main line which is in the basement of the house. So how much do you think it would cost to run plumbing from the detached garage to the house, into the main drain, as well has running water lines to the building?