my storage building is approxiamately 15ft from the bathrooms in the house. I want to install myself, a tub and use the water system from the house, can it be done, and any suggestions. Thank you.
If you can drain the plumbing that way, then yes.
If you don't plan on pumping the waste, then check to see if it will drain downhill between the two spots.
You may be required to go with a 3" or 4" pipe in the ground if there is some distance between the two.
Getting water there is easier, you will want to insulate the hot water.
You might want to check with the local plumbing inspector there to see if your plan is okay in that area.