garage plumbing questions

[boyack123]

Im currently drawing up a 26 x 24 garage . would like to install 1/2 bath (no shower) I plan on using tankless water heater. My question is garage sewer line run will be 190'. With that long a run.
Will 3" pipe be okay with the distance? I can get the slope.
For just a toilet and sink do I need a 3" vent?
Must I have a end of line clean out? (I can pull the toilet if problems arise).
Or can I have a 2-way clean out at bldg wall?
The main drain will come through slab with the water supply all additional plumbing will be under a raised platform/floor. The vent piping examples I'm finding all deal with toilet, sink and a shower or tub. Any resources someone could point me to would be greatly appreciated.

 

[493mike]

Is this an "off the record" project? If so a 1 1/2 vent will suffice. 3" sewer is correct. The C.O. is for your benefit and I would do end of line although, you don't want much dead line upstream from the last fixture drain branch. If you are pulling a permit, then follow your local plumbing code.
Mike

 

[readhead]

Why a raised platform? You are only talking two drains and one is already in the concrete.