"The city last June limited the use of lawn sprinklers to Mondays and Thursdays, and those restrictions have proved highly successful. Officials said Tuesday that in February, Los Angeles had its lowest recorded water use in 31 years.
But the water conservation policy was too much for the city's aging network of cast-iron pipes, causing fluctuations in water pressure that strained them to the bursting point, the panel's long-awaited report found. Its conclusions appear to put to rest other theories about the cause of the mystery, including increased seismic activity."
Because of the dramatic rise and fall of water pressure on those days, the area's aging water pipes were likely put under too much strain and burst. Officials are rethinking their policy and trying to find a way to avoid similar breakages in the future while keeping the conservation effort intact.