We had the temperature drop below freezing for several nights in a row a few weeks ago, and it brought to mind another issue about wells--- or at least my well.
Our well pumps water into a small pressure tank prior to pumping it up the hill to our house. Which means there are several feet of exposed pipe. And, when it freezes... well, so does the water in the pipe, which means no water gets pumped.
To combat that I use heat tape. Couldn't find any in the hardware stores around here (too urban) to I ordered some online. It works great--- it's just an electrical line encased in a plastic/rubber insulation which radiates heat. Not a lot, but enough to warm the pipe when you affix it with a loop of wire.
My understanding is that heat tape uses a lot of electricity, but I haven't noticed too big a jump in the bill, and it's not like we have a choice. One time when I forgot to plug it in and we got hit by a surprise freeze, my wife had to go down to the well and aim a blow dryer at the pipes so she could take a shower.
Needless to say, I never forgot the heat tape again.