Montgomery County Executive Charles W. Gilchrist, on the eve of a County Council session on whether to spend money to open a landfill in Laytonsville, yesterday said he would oppose a liner for the dump, calling it a needless expense.

Residents of the area near the landfill, scheduled to open this June, have said that they would accept the facility only if a liner and waste water collection system were installed. A liner, made of plastic or clay, would be placed under all waste to prevent possible leaching. Another safety precaution the council has debated is a cap, which would be placed over the waste to prevent water from reaching the waste.

A national firm hired by the residents, as well as two members of the county council, favors a liner. Gilchrist cited a recent letter from the Maryland Department of Health and Mental Hygiene that said that a liner would not increase the landfill's safety. A liner would cost between $14.4 million and $19.3 million, Gilchrist said, was "too large a price to pay" to calm public fears and "abate hostility" generated by the dump's opponents.

"Two administrations have spent millions of dollars . . . to design what scientists have assured us is a safe landfill . . . "said Gilchrist.

Priscilla Benner, vice-president of the Greater Laytonsville Civic Association, immediately criticized Gilchrist's statement, saying "I continue to be appalled by the inability of county officials to deal with the tremendous health threat to our citizens and to our environment."

Councilwoman Ruth Spector proposes extending public water lines to the Laytonsville area, in case leakage would contaminate private wells, an idea Gilchrist said he supports. Spector agreed with Gilchrist that a liner is not necessary and the time to construct one would force the county to keep its Gude landfill open past June 1, the state's deadline for its closure.