Discolored water is caused by the build up of iron and calcium deposits in the waterline. When water flow is interrupted by a line break or fire hydrant flushing, deposits can be stirred up, creating the colored water. It usually takes three-to-four hours for water to clear. Periodically turn on your cold water and let it run for several minutes. Keep doing this until the cold water is clear. Do not use hot water or wash clothes until the water is clear.