Wichita ? Sedgwick County wants to find out how many people live under overpasses, in their cars or in homeless shelters.

Federal grant money hangs in the balance.

Local government and the United Way of the Plains are about to undertake the biggest and most comprehensive count of homeless people ever attempted in Sedgwick County.

And volunteers are being sought to assist with the homeless census.

The homeless population last year in Sedgwick County totaled 589 people, and 195 of those people had no shelter, according to last year’s count.

In 2006, the federal grant was for $1,907,841, said Beth Oaks, vice president for community planning and resources for the United Way. This year’s grant request is $1,912,786, she said.

County Manager William Buchanan said the survey also will help to guide decisions made by a task force set up to address the needs of the homeless population in the community. The task force consists of city and county officials, homeless people, charity workers and service providers.

Buchanan said the homeless population is not homogeneous, noting that some have lost their jobs, some are fleeing abusive spouses, and others live on the streets because of mental illnesses.

The upcoming survey also will gather demographic data to help officials decide where to best concentrate their efforts, Buchanan said.

Survey organizers are seeking 160 volunteers. Most will be asked to serve a four-hour shift on Jan. 23 or 24, said Bob Lamkey, county public safety director.

Lamkey said the bulk of the volunteers will count people at shelters, food programs and other institutional settings. Those volunteers who count the homeless in parks and on the street will be paired with experienced officials from agencies that regularly work with the homeless.