It appears likely that city residents will see a 12 percent increase in water rates in 2009, in part, because city commissioners no longer want to gamble on a key piece of aging infrastructure.

At a study session Monday afternoon, commissioners did not object to City Manager David Corliss’ proposal to increase water rates for the coming year. Commissioners were told that the average household that uses about 8,000 gallons of water per month would experience an increase of about $3.15 per month. People who heavily water lawns or gardens would see larger monthly increases.

“From the information we’re getting, we still would be pretty much in the mid-range of what other cities charge,” City Commissioner Mike Amyx said. “But it still will be a hard pill to swallow, obviously.”

Staff members, though, said the rate increase is needed because concern is growing about a 34-year-old water intake on the Kansas River. The intake is the sole way the Kaw Water Treatment plant captures surface water from the Kansas River. If it failed, the city would have to rely on the Clinton Water Treatment Plant on the western side of Lawrence. That plant likely could not meet all the city’s water needs, especially during the summer.

“You would be talking about rationing,” Amyx said of a worst-case scenario.

The intake would cost about

$6.6 million to replace. City staff members said they did not think the intake was in immediate danger of failing, but history shows the devices do fail when they get old.

Other intakes on the Kaw have lasted about 30 years, on average, before the piping has been washed out.

Replacing the intake likely will mean North Lawrence residents will have to wait longer for a major water system improvement. Commissioners were told that even with a 12 percent increase the city won’t have enough money to do both the intake project and a $6 million project to run a new water line across the Kansas River to North Lawrence.

The waterline project was designed to give North Lawrence a second source of water. Now, North Lawrence receives all its treated water from a single 19-year-old water line that runs underneath the Kansas River bridge near Massachusetts Street.

Subsequent phases of the project would run the water line back across the river to eastern Lawrence to serve the area near O’Connell Road and 23rd Street.

Commissioners, though, agreed the Kaw water intake project was more critical.

“That is the one where we face the highest level of risk,” City Commissioner Rob Chestnut said. “If that intake goes down, we would have a serious problem.”

Commissioners are hoping the 12 percent rate increase doesn’t cause serious problems for rate payers. Staff members presented information that showed Lawrence’s water rates are the second-lowest among nine cities and water districts surveyed in the Kansas City and Topeka area.

Commissioners also are not proposing a sewer rate increase for 2009. That means total sewer and water bills are expected to increase by about 5 percent on average.