Attached is a rendering of our first floor kitchen and half bath, with our second floor fixtures drawn on in orange (toilet, sink, tub/shower) and an access panel and the tub supply line direction in green (panel on landing of stairs, supply lines seem to be originating from exterior wall at top of photo on opposite end of tub from the faucet). This house was built in 1952, I’m wondering if anyone can suggest where on the second floor the tub and sink/toilet supply lines are routed? There is only one supply from the basement up to these two bathrooms (directly below the first floor half bath sink), so they must come together somehow. I realize there’s no knowing for sure without pulling up the floor or breaking into the walls, but I’m curious to know what kind of layout is most likely, if any. I thought maybe they would avoid an exterior wall, but that leaves only running them under the second floor full bath floor?