Two water lines froze on me... One to crapper in wall and a short section i moved this year so it wouldn't freeze(i meant to heat tape it)...
New well room I built and insulated the hell out of is a balmy 55 degrees with a small bathroom heater.
Bet all my neighbors wells froze.
We seldom get down to mid teens here and has been probably 4 years, heater worked well actually was almost hot in house last night.