Preventing frozen pipes
Water supply pipes in unheated areas and pipes near exterior walls are the most prone to freezing. Keep these areas warm by adding insulation to attics, basements and crawl spaces and insulating both hot and cold water pipes with a sleeve or heat tape. Allow warmer air to circulate around plumbing by keeping garage doors closed and opening kitchen and bathroom cabinets. Also, never set your thermostat below 55 degrees. Keeping pipes warm is a lot more efficient then letting water drip.
If you turn on a faucet and only a trickle comes out, suspect a frozen pipe. To thaw, first keep the faucet open (turned on). This will allow a place for the melting ice to flow. Additionally, the water flowing through the faucet can help melt the ice. Apply heat to the section of pipe you expect to be frozen (e.g. near exterior walls or in a crawl space.) Try using an electric heating pad, hair dryer or portable space heater. For safety, NEVER apply an open flame, such as a blowtorch or propane heater. If the water does not return to a normal flow, a professional plumber may be necessary.