When the water in the lines is agitated (for example from a large water main flush, road work, or hydrant use) this can stir up sediment (primarily iron) from the bottom of the water lines. In the course of normal maintenance, the hydrant flushing and water gate exercising can stir up this sediment.
If your tap water does appear reddish or rusty in color, it is recommended not to use your water for one hour, and then run the cold water at the lowest point in the house for several minutes. If water is still not clear, wait for another half hour then run the water for several minutes again. Repeat waiting for a half hour then run water for several minutes until water runs clear.
The water is still potable but the discoloration may affect the washing of clothes.