City planning officials say Lawrence is growing faster than indicated by last week’s U.S. Census Bureau estimates.

The bureau numbers, released Wednesday night, suggest Lawrence had a population of 82,210 on July 1, 2003 — an increase of just 2,000 people from the last count in 2000. If correct, that would be a considerable cooling off from the 1990s, when the city grew an average of 1,449 people a year.

“You’re kidding,” Lawrence-Douglas County Planning Director Linda Finger said of the census figures. “I’m sure we have our population much closer to 88,000. I wonder what they’re basing their numbers on.”

In fact, city planner David Guntert said, City Hall’s estimate is that Lawrence had a population of 87,184 as of Jan. 1. If the city numbers are correct, Lawrence has been growing 2,362 people a year since 2000.

“Their (numbers) certainly aren’t following the same path ours are,” Finger said.

Why it matters: Major planning decisions — including a proposed $64 million sewage treatment plant for the Wakarusa River — hinge on how fast the city is growing. Officials have said the plant was needed because they expected Lawrence’s population would reach 100,000 in 2011, pushing the existing Kansas River plant to its capacity.

If Lawrence is actually growing by 674 residents a year, as the Census suggests, that capacity wouldn’t be reached until closer to 2030.

And that has city officials wanting a closer look at the city’s actual population.

“I think we need to know that,” City Commissioner David Schauner said, “because if we’re going to base decisions on the numbers … we ought to know.”

The Census Bureau did find growth in areas around Lawrence from 2000 to 2003. For example, Tonganoxie’s population shot up by 21.6 percent to 3,317, the bureau estimated. Eudora, the bureau said, grew 15.2 percent to 4,963.

Guntert said City Hall based its population estimates on the number of building permits issued in Lawrence, subtracting the number of houses that were demolished.

“Since the 2000 census, we’ve built 2,000 new housing units in Lawrence,” Guntert said. “Are they saying there’s only one person per housing unit?”

But Greg Harper, with the U.S. Census Bureau, said his organization made its city estimates using similar data. He couldn’t account for the discrepancy in city and federal estimates.

“There are often differences when you use different methods,” Harper said.

City officials offered anecdotal evidence last week to demonstrate their contention Lawrence was growing faster than federal estimates suggested.

“I was out driving a little bit last night, and I was stunned by the number of houses being built around Free State, for example,” Schauner said. “It wouldn’t be my anecdotal observation our growth is slowing.”

City Manager Mike Wildgen also cast doubt on the census estimates, noting the bureau showed a population growth of just one person, from 2,214, in Wakarusa Township.

“It’s hard to believe it went up one in Wakarusa,” he said. “They’re building houses all up and down there.”

Finger said her staff would contact federal officials to reconcile the numbers.

“Being conservative is generally good, but because population has become such a critical component of master plans … I think it would benefit staff and the city to meet with census and try to come up with how their number is so different than ours,” she said. “That’s quite a margin, there.”