I'm definitely a novice when it comes to things like this so please bear with me. We bought our 1956 slab on grade home 2 years ago. From doing some remodeling I've noticed that in at least 3 spots in the house (washer, shower, outside spigot) has copper water pipe coming up through the slab and supplying water. However when opening some small spots in our drywall I've also noticed that in the wall sections I will sometimes find sections of galvanized piping used to provide water (hot and cold on sinks etc) but I've of course never seen the galvanized piping coming out of the slab. Was it normal to sometimes use galvanized pipes for certain sections when what I'm assuming (based on seeing the copper coming in out of the slab on 2-3 occasion) is copper that is ran under the slab?