Go figure

The cap I put on the line to the hot water heater did, in fact, cut off the water leaking from the hot water lines.  So it appears I'm not crazy after all.  Now I just have to replace one cutoff and I might have water out to the carriage house.

Upstairs will be a different issue.  Just for laughs I tried turning that on -- water came gushing out above the entry stairs on the first floor.  So I'll be taking up the floor in the front bedroom upstairs to fix that.  Later.

Here you can see where I mean.  Clearly this isn't the first time there's been a leak there.