Sonoma leaders Monday voted to declare a Stage One Water Shortage Alert, a step that formalizes a call for residents to voluntarily reduce water use by 15 percent.

The move took place on the same day that a Sonoma County Water Agency panel voted to ask all its contractors - including Sonoma - to voluntarily cut water usage by 20 percent.

The Sonoma council set a 15 percent limit because its municipal code steps out levels of water rationing and City Engineer Dan Takasugi said it wouldn't be necessary to amend the code to comply with the water agency request.

"We do want to achieve that if we can and we're going to do the best we can," Takasugi said of the 20 percent target.

Robert Taylor, a resident, said climate change models suggest that the state may be entering a state of permanent drought and said the council should act more forcefully that asking residents to join the effort to save water.

"I would urge the council to consider more aggressive measures," he said.

The council declined to, but agreed that the situation should be revisited in March.

If nothing changes, said Councilman Steve Barbose, "We can't be going into the summer with voluntary 15 percent."

Addressing Taylor, Councilwoman Laurie Gallian noted that the city would not normally consider the step it was taking until April or May. For it to be taken in the beginning of February was, she said, "a sign for people to stand up and pay attention. For me this is an urgent measure."