Can you add a valve to the tank to keep something in it to keep it primed, while you cut the water to the rest of the house? Maybe you could put a heating coil in it to keep it from freezing?

Before we gutted our house (due to be finished in three weeks), I showed up one weekend and discovered I had a wading pool in the basement, due of course to a frozen and burst pipe. It burst in a room that we thought was heated. Anyway, instead of replacing the pipe, because it was just going to get ripped out for the renovation, we simply put two valves on the ends of the pipes. When I'd leave each time, I would cut all the water to the house, then drain everything through those two valves. Now, we have a spigot at a fairly low point, and better heating in the basement, so I'm much less worried.

Can you cement the joint at which there is a leak?