What is the cheapest (yet correct) amount to add a bathroom?

[Michael Johnson]

Hey BPers, quick question. I found a 4bdr 1ba. So I would go ahead and call that functionally obsolescent?? Especially if I want to rent out each room individually. I know there are 1,001 variations but I have no idea how much it would cost. So im just looking for really rough numbers or a range. 

If it makes it easier dont include the vanity and tub. Im looking for the plumbing, construction, and permits I guess. 

Thanks!

[Michael Hayworth]

Varies dramatically. You're talking about mainly the infrastructure, not finishes such as vanity, tile choices, etc. I've done it as cheap as $3000 or so, and had it cost as much as $12,000. (Then, of course, figure a few thousand for vanity, tub or shower, the toilet itself, tile, etc.)

The main issue is that a toilet requires a minimum 3" drain line, and nothing else in the house does. So being near plumbing for a kitchen sink, washer, etc. doesn't help. You have to be able to either hook into the 3" line for the other toilet, or go direct to the main drain for the house, and have room to have 1/8" fall per foot of pipe along the way. Sometimes, this is a piece of cake. Other times, it's very difficult.

Best case is if you can build adjacent to the existing bathroom, but that's layout-dependent.

Good luck.