Welp, this drunken yankee polar freeze got me.

Cold water line to the shower busted. First time in nearly twenty years. Fortunately, I can access it through a small closet and won't have to lay in cold mud to get it done.

Outside wall?

Lucky you have ez access....

Yup, outside and years ago the floor was made removable for access to the shower fittings. It's a shower tub and if originally reversed the pipes would've been on an inside wall. The closet is just a tiny 16" linen closeton the back wall with the lines underneath the house just inches from my swiss cheese foundation. Original brick piers closed in with block.