Sonoma's City Council on Monday night unanimously rejected raising water rates by at least 25 percent over the next five years amid concerns that the city has not explored other options, including consolidating services with other water agencies to cut costs.

"I think we have a little more due diligence to do," Councilman Tom Rouse said.

The city Public Works Department sought a 5 percent rate increase for each of the next five years to help offset a projected deficit in the water budget and to pay for capital improvements, such as replacing aging wells.

The city buys 95 percent of its water from the Sonoma County Water Agency and in recent years has absorbed increases in those costs, according to staff.

Public Works Director Milenka Bates told the council that without the rate increases, the city would have to defer projects and "fix things as they break."

She said the capital improvement budget of $1.91 million is enough to fund the city's water needs for two years. The city also could sell water bonds as another source of revenue, she said.

About a dozen Sonoma residents spoke against the proposed increases, saying they would hurt seniors and others on fixed incomes.

"We have been nickeled and dimed to death in the last five years," said veteran council watcher Herb Golenpaul.

Mayor Joanne Sanders called the proposed increases an "assault" on families.

"We can only brown our lawns so much, but we still have to eat and flush our toilets," she said.

Sonoma's service charges for water use are the third highest in Sonoma County behind Rohnert Park and Larkfield.

Under the proposal for the first year, the average water bill for a typical single-family residence would have gone from $61.47 to $64.43. That's for a family that uses about 9,000 gallons of water in a two-month period.

Several council members said the city should possibly explore consolidating with the Valley of the Moon Water District to try to cut costs.

Sanders said the fact Sonoma has its own water department "seems like a luxury" given the city's small geographic size.

Council members also raised concerns about how much the city is having to pay the county water agency and how much of that amount is related to overhead, such as salaries.

Councilman Ken Brown said "safe water costs money," and he predicted if the city does not provide it, there would not be a building large enough to accommodate the angry crowd.

They will "come out with their flames and their pitch forks and everything else at their command," he said.

You can reach Staff Writer Derek Moore at 521-5336 or derek.moore@pressdemocrat.com. On Twitter @deadlinederek.