SAN RAFAEL – A closely watched vote that would allow construction of a new home for the Marin Farmers Market at the county’s historic civic center campus seemed poised to pass by overwhelming majority on Wednesday, with an official tally released after the close of polls showing 81 percent of voters in favor of the proposal.

The Marin County Registrar of Voters released those results late Tuesday, representing participation of 29.2 percent of registered voters in Marin. A final tally will be made available June 6.

Passage of “Measure B” will authorize the Agricultural Institute of Marin, which operates the market, to go forward in the process of establishing a permanent home at the Frank Lloyd Wright-designed Marin Civic Center. The twice-a-week market has operated in various vacant parking areas for over three decades, attracting thousands of visitors and over 200 vendors every Sunday.

Marin County residents passed a ballot measure in 1992 that mandated majority voter approval for all new civic center buildings. The market proposal has garnered a large degree of public support, with no opposition included in ballot materials.

The structure itself would be built at the vacant lot usually used to sell Christmas trees at the civic center campus, occupying no more than 30,000 square feet. A light-permeable canopy will provide weather protection for vendors and visitors, joining education and event facilities and a seven-day-a-week market hall selling locally produced goods and foods. A small business incubator is also planned.

The Agricultural Institute of Marin is looking to the public as it seeks to raise up to $20 million for construction of the new facility, though $10 million would be sufficient to move the project forward. The market would be built at no cost to taxpayers.