From FEMA'S "Are You Ready--An In-Depth Guide to Citizen Preparedness"
Turn off the main water valves. You will need to protect the water sources already in your home from contamination if you hear reports of broken water or sewage lines or if local officials advise you of a problem. To close the incoming water source, located the incoming valve and turn it to the closed position. Be sure you and other family members know how to perform this important procedure.
* To use the water in your pipes, let air into the plumbing by turning on the faucet in your home at the highest level. A small about of water will trickle out. Then obtain water from the lowest faucet in the home.
* To use the water in your hot water tank, be sure the electricity or gas is off, and open the drain at the bottom of the tank. Start the water flowing by turning off the water intake valve at the tank and turning on the hot-water furnace. Refill the tank before turning the gas or electricity back on. If the gas is turned off, a professional will be needed to turn it back on.
Safe water sources include:
* Melted ice (like from the freezer, not from the driveway)
* Water drained from the water heater
* Liquids from canned goods such as fruits or vegetables (hmm....I'd take issue with this. The liquid from canned vegetables is FULL of sodium and the liquid from fruit is full of sugar. I'd use this as a last resort)
* Water drained from pipes
Unsafe water sources include:
* Water beds
* Water from the toilet bowl or tank
* Swimming pools and spas (chemicals used to kill germs are too concentrated for safe drinking but could be used for personal hygiene)