Down here in Florida people do two things when we know a freeze is coming. Wells down here have spigots on them that you can open and let the water trickle out at enough of a rate that the switch comes on often enough to avoid freezing. Another trick people have done is taken bird houses, put them over the pressure switch (That's what we call it here, at least) and install a light inside the bird house. One you can plug in or wire to a switch and flip on. The heat of the incandescent bulb keeps it warm.