What are the rough in dimensions for a 30" vanity, supply and drain, going through the floor.

Put the hot and cold wherever you want depending on the faucet (1 hole, 4", 8") because they are flexible. Get a 1 1/2" drain kit and measure backwards from the center of the basin to the center of the pipe where it will go through the floor. You have some leeway there too. If you don't have the faucet or top, put the drain in the center about 1 1/2" from the back.

The rough in dimensions for a lavatory sink are usually:

18" off the finish floor to center of the drain tee fitting and then install an AAV (mechanical vent) up another 6" or so. The drain pipe should be about 3" to left (or right) of the center of the sink.


22" off the finish floor to the center of the water pipes. Water pipes should be 4" left (hot) and 4"right (cold) of the center of the sink.
Good luck!

Mark