plumb question: what is this

Bradenton FL

Description

folks on craigs list have been an incredible fount of knowledge for me over the years....I have another question to ask about a tiny copper pipe on the outside wall of my house-- I have added four pics...first shows the side of building, and each subsequent pic shows a closer pic of the issue I wanted to do this to add an idea of size..or lack of it, from the copper pipe...it is tiny At the bottom of the outside wall to the bathroom, I have a tiny stream of warm water coming from a copper pipe. I did a series of pics to show how small the diameter of the pipe is...I thought that it was a drainage pipe from hot water heater? had the pressure valve replaced, as it was defective, but still no decrease in the tiny stream it is on the out side wall, and the hot water heater is in the same room but quite a distance away. There is no obvious pipe on the floor, so must be in the wall...I can cap it, but wanted to know what the heck it is...thanks in advance to ideas offered