I know it has been asked and answered many times.

Is there a way to test it though? Or do I just go with "it should be"

This is a 1993 build in MI with the 3 pipe slabed rough-in.

I need to slot the slab and move it 4 feet-ish so as to put a shower unit in. the rough-in was for tub/shower combo and is too close to stool given size of available space of room.

Will this be a problem to continue the slope of the drain for an extra 4' ?

Once slab is cut and recemented I can tile the floor and install the stool. Is there and code I should be worried about in the supply side. Very comfertable with sweating copper so not a problem there. Will run 3/4 to shower then 1/2 to sink and stool.

Thank in advance
Slash

The 4 feet shouldn't be a big issue.. what is more likely to be an issue is that the tub/shower combo. Only requires an 1.5" drain line and showers need 2" pipe. If 2" pipe is present then you are all set. If not and connection into the toilet drain is close by it would be a good idea to increase the size of the drain to 2". You can still use the 1.5" vent pipe (or 2" wet vent) that should be present to vent all this.

If you don't want to increase the pipe size you could always install a pipe increaser and upgrade to 2" pipe, but the shower drain will probably have a tendency to clog sooner than it would have if you upsized as code requires.

In terms of water pipes, if you are installing a 3/4" shower valve then run 3/4" pipes to the shower valve, but if you're not installing a 3/4" shower valve, but just a regular 1/2" shower valve, then just branch off at the sink with a 3/4"x1/2"x1/2" tee fitting and run 1/2" to sink and to shower. You should be all set thereafter... ;)

Let me know if you need more...

MARK