Montgomery County Executive Douglas M. Duncan, averting a legal showdown with the American Civil Liberties Union, yesterday proposed eliminating the county's 30-day limit on the posting of yard signs.

He asked the County Council to scrap an eight-year-old provision of the zoning code that requires residents who exceed the limit to apply for a permit and pay a fee of $29.70.

Duncan's proposal follows a letter the ACLU sent to the county attorney's office two weeks ago threatening legal action if the 30-day limit and permit requirement were not removed from the code.

Citing numerous legal rulings, ACLU attorneys said the provision was unconstitutional because it infringed on the First Amendment right to free speech.

The ACLU represents a group of residents who erected signs to protest plans for construction of what they saw as an oversized house in their Chevy Chase area neighborhood, Brookdale. A limited liability corporation headed by Thomas R. Eldridge, a developer and Somerset Town Council member, bought a 21/2-story house in Brookdale in March and tore it down. The corporation has since broken ground on a house that residents contend will be four stories.

In August, several dozen residents posted signs in their yards that read, "Council Member Eldridge, We Don't Want Your McMansion for Profit in Our Neighborhood!"

Early this month, the county Department of Permitting Services, which in July approved Eldridge's plans for building the house, said the signs had to go. When six residents refused, they were issued a violation notice, the first step toward fines that could have approached $500.

After several days of discussions between the county attorney's office and ACLU lawyers, Duncan (D) agreed to propose the code changes.

"Requiring a private owner to apply and pay for a permit in order to post a sign on private property raises First Amendment issues," Duncan wrote yesterday to council President Tom Perez (D-Silver Spring).

Duncan's proposed changes require council approval. Until the council acts, the Department of Permitting Services has agreed to stop enforcing the 30-day limit.

The change will mean residents can post political signs or advertisements on private property year-round. But the signs must adhere to other zoning regulations that limit them to five feet in height and at least five feet off the property line.

ACLU officials applauded Duncan's position.

"A spirit of cooperation has prevailed," said Richard Griffiths, an ACLU attorney who wrote to Duncan yesterday saying the organization will drop its plan to sue the county.

Griffiths said the restrictions, which have been in effect since 1997, are "offensive to speech."

Last month, the ACLU won assurances from Emmitsburg in Frederick County that it would remove time restrictions from its sign ordinance, Griffiths said.