Most Napa Valley farmworkers are residents of Napa County, and many have never heard of the county's three farmworker centers, according to a new report on farmworker housing demand from a rural think tank.

The Davis-based California Institute for Rural Studies plans to outline the findings in its study to the newly created Napa County Housing Authority on Tuesday.

The study found that there were 6,790 farmworkers in Napa Valley in 2005, and that 64 percent lived permanently in Napa County. Most of those -- 86 percent -- in an apartment or a garage, according to the study.

About 21 percent of farmworkers said they had never heard of the valley's farmworker centers.

About 40 percent of farmworkers were accompanied by a spouse, with 32 percent of farmworker households reporting children under the age of 18. About 35 percent of farmworkers lived in adjacent counties or in the Central Valley.

The institute will make several recommendations for managing farmworker housing, principally to keep housing center costs competitive with the economic demands of migrant workers. Many migrants are single men who have obligations to send money home to Mexico. The institute estimated that about $250 per month in housing costs were consistent with that need. The institute also recommended finding some way to advertise the centers, something the current operators are doing now with flyers and radio spots. The institute also recommended creating more affordable housing for families in Napa County.

"More and more we're seeing farm labor shortages, so it has become more and more important for agricultural areas to attract a quality workforce," said Ron Strochlic, executive director of the institute.

The study is the first of its kind for Napa County for at least the last several years, according to Howard Siegel, Napa County's community partnership manager. The study is the result of legal pressure from groups that sued the county over a lack of affordable housing in years past.

"This basically grew out of a lawsuit," Strochlic said. "Hopefully something good will come out of this."

The study paints a picture of farmworker life at a time when the county is due to take control of farmworker centers in the valley in the wake of wake of financial mismanagement by the previous agency, the Napa Valley Housing Authority.

The county took over administration of the farmworker centers from the Napa Valley Housing Authority in April, after former director Peter Dreier used $1.4 million in the city of Napa's housing reserves without authorization to cover construction cost overruns at the Mondavi and Calistoga farmworker centers last year.

Dreier retired under pressure in December. Local lawmakers are still in negotiations over how to cover the cost overruns. Meanwhile, the new Napa County Housing Authority passed a $1.2 million budget last week for the current year, estimating at least $971,000 in costs to run the farmworker camps.

Pam Kindig, county auditor-controller, said a draft audit of the Napa Valley Housing Authority's actions is due to be presented to the county on May 15.

Siegel said the county has little idea of what occupancy rates will be at the two newly-renovated farmworker centers, which have had vacancy problems before new construction. But Siegel estimates the county will be up to speed on how to run the centers within six months of a July takeover date.

The county is negotiating with the California Human Development Corporation, the current contractors hired to run the centers.

"Hopefully we will have the benefit of the same operations firm that has been managing these camps," he said. "Hopefully we will be doing what has been done. ... We won't be reinventing the wheel."

Siegel said the farmworker centers, which have 180 spots available, are targeted toward a small population of farmworkers who might otherwise not find housing during peak grape production times.

"It clearly is the focus for the folks that are here less than twelve months out of the year," he said.