Sebastopol's water and sewer rates will double over the next four years.

The increases, the first since 2008, are needed to offset the increasing costs of supplying water and sewer services and pay for maintaining and replacing the city's aging systems, council members said.

Residents, however, will be hit hard by the new rate schedule, approved on a 3-2 vote late Tuesday.

A typical water bill over four years would increase from about $10.79 a month to $24.92 and the sewer charge would go from about $25.67 to $49.92, according to city staff.

"It is regrettable, but the result of many years of not acknowledging the reality of the situation," said Mayor Guy Wilson. "Our rates were among the lowest in the county, and part of the reason is we did not charge the true cost of the system in terms of the water fund and having money set aside to upgrade the older portions of the system."

Wilson and council members Patrick Slayer and Sarah Gurney voted for the increase.

It was opposed by Vice Mayor Michael Kyes and Councilwoman Kathleen Shaffer.

"The staff said we need an extra $500,000 a year to do replacement for our underground piping, which is reasonable. However the increase doubles the rates. We are raising more than we actually need, to me," Kyes said. "I didn't find any satisfactory answer for that."

Notice of the rate increase will be sent within the next three weeks to every Sebastopol property owner, who will have the chance to file a protest.

The council will hold a public hearing and consider final adoption of the rates in August, said Larry McLaughlin, the city's attorney and interim city manager.

The city's water and sewer systems are intended to be self-supporting, with the fees covering all costs. However, the city is facing a decrease in fee revenue, an increase in operational costs and the need to replace and repair the systems.

Sebastopol bills residents on a bi-monthly basis.

For comparison, city staff converted the new rates to monthly costs and said they would still be less than all but Cloverdale.

On a monthly basis, Sebastopol residents would pay $105.31 for both sewer and water in the first year of the new rates. In comparison, Cloverdale residents pay $61.46, Cotati $120.49, Healdsburg $122.81, Windsor $126.91, Rohnert Park $131, Petaluma $144.29 and Santa Rosa $165.50, according to city staff.