: I'm having a concrete slab poored for a new garage and want to run pipe for a "future" toilet and shower stall installation. What is the "standard" measurements from the wall for the toilet flange and the shower stall (36"x36")drain? Your help is appreciated.

Alan,
For the toilet, you can figure 12" from the "finished wall", and from the center of the toilet to the either side, you should have 15".

The water supply is safe at 8" from the left of center, and five inches off the floor.

For a 36x36 shower pan, most of the time, you can divide the numbers in two. 18x18 measuring from the face of the studs. Since the pan sets up against the "unfinished wall" it will be measured differently than the toilet.
Not all shower pans have the same dimension on the drain though. I like to have the pan bought first before I set the drain center.
I like to leave off the p-trap during roughin and leave a cardboard box filled with dirt over the drain location.
Then when the walls are framed in, and with the shower pan on the jobsite, I can install the p-trap right where I want it. A little bit of digging and I can find the pipe to work with.
Terry