When temperatures get down into the low 20's that is when the frozen pipe alarms should go off. Disconnect all outside hoses, buy inexpensive foam faucet covers for outside faucets. As far as indoor faucets, it all depends on your homes plumbing layout. But here are some tips (courtesy of our friends at KATU) on how to keep your water pipes from freezing and what to do if they do burst. By the way, if for some reason you can't disconnect your outside hoses before the freeze, leave each one on so just a trickle comes out. This will allow the water to expand as it freezes and hopefully keep hoses of faucets from bursting. Get more tips here.