In recent flooding I started excavating our (cracked, failing) concrete basement floor. (it's just a thin layer over a dirt floor–old house)
I stopped when I found a 1/4" copper line buried in the concrete. It's heading toward the heating system. But that was upgraded to gas some time ago, and I can clearly find the gas lines (they're overhead). Doesn't seem like electrical conduit. Doesn't seem like water pipe, but…who knows.
Any idea what this might be? Why would a tiny water line be heading to the heater? For now I've marked it so I don't disturb it.
Best Answer
More than likely it was an oil fuel line. It was very common to encase oil lines in the floor until recently. Gas would have been in black iron pipe. Maybe water, but 1/4 inch too small for anything but an ice maker in a fridge.