I just purchased a new home which has a bathroom roughed in the concrete floor of the basement. The dimension for the toilet is 15 inches, which means I can use a 2x4 wall. However the drain pipe for the bath tub from the same wall is 59 inches. I think this is a problem for a 2x4 wall because this would make the drain less than what I think is required. Can someone tell me what the standard wall rough in dimensions are for the drain for a bath tub are, from each wall. This would be from the foot of the tub to the drain, from the head of the tub to the drain, and from the side of the tub to the drain. Before I install the wall, I want to make sure a tub will fit. One last question, I want to install a small bar sink on the other side of the tub head wall. Can I tee into the tub drain to drain this bar sink?

We rough our tubs in at. 15 1/2" off the side plate to the center of the trap raiser and 1 1/2" off the front plate. Those are all the measures that you need.
"I want to install a small bar sink on the other side of the tub head wall. Can I tee into the tub drain to drain this bar sink?"
No, the bar sink trap will have to have a vent of its own. If you connected to the tub drain you would be building a "S" trap which is illegal. Good luck, Tom

Thanks for responding. I understand you to say that the tub enclosure should be 15-1/2" from the side and 1-1/2" from the head, which, for a 60" tub enclosure, would be 58-1/2" from the foot? Any ideas how to get a drain from the bar sink?

Any ideas how to get a drain from the bar sink?
Yes, wye off downstream from the tub trap for a drain and revent the bar sink back into a existing dry vent. Good luck, Tom