Water consumption dropped 13.5 percent in California in April compared to the same month in 2013 before water saving measures went into effect, as the western US state fights a debilitating drought with mandatory cuts.

The decrease is far less than the 25 percent conservation rate ordered by Governor Jerry Brown, though still much higher than in previous months, according to the State Water Resources Control Board.

But the figure fails to show the uneven consumption between different areas, with some regions showing big drops while others such as El Segundo saw a 35 percent increase in its water use.

"While these results are a step in the right direction, there are still too many lush landscapes where irrigation must be reduced to meet the 25 percent statewide reduction mandate," State Water Board Chair Felicia Marcus said in a statement.

"We see conservation gains in all regions of the state, but we don't know whether it was because of cooler weather or concerted action."

Los Angeles has launched surcharges that double normal water prices for clients who do not respect 30 percent mandatory cuts in three zones, including the affluent beach city of Malibu where many stars' luxurious homes are located.

Residents of Malibu have been asked to participate in further water cuts of 36 percent.

"The real test will be what happens as we move into the hot and dry summer months, when we need to keep the sprinklers off as much as possible," added Marcus.

Cuts between an 11 month period between June 2014 and April 2015 amounted to a 9 percent drop.

2013 is used by the water board as a baseline year for water use comparison because it is before emergency water conservation measures began in the state.