The mother of all leaks

This video was taken at one of our rentals, through a hole the plumber cut in a closet wall into the hall bathroom, in order to access the open space behind the shower/tub faucets. It may take a second to realize what you are looking at, but yes, there is really THAT MUCH WATER running inside our rental. It’s like a mountain stream. Where is it going? We don’t actually know for sure. Under the house and away somewhere.

That is actually the lower cost of the two leaks, because it’s accessible. The other one, which has not been accessed yet, is going to require jackhammering through the cement slab. That’s the one that’s going to be very expensive. When done with that fix, we’ll have to repair the slab and retile the bathroom floor.

These leaks are both off the hot water line leaving the hot water heater. I do not understand why there’s two leaks at once. Was there one leak for a long time, and we just didn’t realize it until there was a second one? Are there even more leaks, and we just don’t know about it because they aren’t making the hot water heater run continuously like these two were?