On extreme "polar vortex" nights, run a tiny trickle of water through the fixture farthest from the street. Moving water takes much longer to freeze than standing water. However, remember that if the waste pipe is frozen, this will just fill your tub.
If you have an exposed pipe in a basement, you can wrap it with self-regulating heat tape. Plug it in and let the thermostatic technology do the work. frozen waste pipe
Congratulations (or rather, condolences), you likely have a frozen waste pipe. On extreme "polar vortex" nights, run a tiny
A frozen waste pipe is a race against the clock. Act fast, use gentle heat, and never let desperation drive you to a flame thrower. Stay warm, and good luck un-gunking those pipes On extreme "polar vortex" nights