A house is divided into apartments, one on each floor. For one floor which is sometimes unoccupied for lengthy periods, there is a water valve to shut the water off for the whole floor. This mitigates against water leaks developing when the floor is vacant....
There is another shower underneath with easily removable PVC ceiling and access to the pipe. So indeed theoretically I could put the valve in the shower ceiling of the lower apartment. But that segment of pipe is galvanized steel, so I would have to cut it and add threads. I actually have the ratcheting tool to do that but I would still need to buy the threading die. It’d be a bit weird if the lower apartment had the control over the water above. Not a show stopper but I think there are better options.
If you have access then you can run a new line away from the bathroom, put a new shut off anywhere you want and then return it back to where you started. Think of a big loop with just a shut off on it.
Is there a basement or crawl space underneath?
There is another shower underneath with easily removable PVC ceiling and access to the pipe. So indeed theoretically I could put the valve in the shower ceiling of the lower apartment. But that segment of pipe is galvanized steel, so I would have to cut it and add threads. I actually have the ratcheting tool to do that but I would still need to buy the threading die. It’d be a bit weird if the lower apartment had the control over the water above. Not a show stopper but I think there are better options.
If you have access then you can run a new line away from the bathroom, put a new shut off anywhere you want and then return it back to where you started. Think of a big loop with just a shut off on it.