A water main break can be caused by a variety of factors. The most common reason for a break is extreme temperatures. Extreme weather causes the ground to expand or contract, adding unnecessary pressure on the pipe. When the pipe can no longer take the extra strain, it bursts. Other common causes include human error (as is the case in San Francisco), age, and corrosion.Although this incident happened in a commercial area in San Francisco, water main breaks can happen anywhere else in the state, especially residential areas in cities like Redondo Beach and Culver City. Water main breaks occurring in such neighborhoods can be more problematic. The flood that comes with a water main break can overflow from the streets and cause extensive water damage to Redondo Beach and Culver City homes, especially those with basements.