An unusually large number of Montgomery County landlords have announced planned rent increases in the past week under the county's newly relaxed rent control guidelines, suggesting that large numbers of county tenants may soon be paying higher rents, the head of the county Office of Landlord-Tenant Affairs said yesterday.

At least 20 landlords have sent out valid notices of rent increases to nearly 1,000 tennants since rent control in the county expired Dec. 31, according to Thomas Hamilton, executive director of the office.

Most of the increases - which will take effect April 1 - are within the voluntary guidelines that replaced rent control and that currently allow an increase up to 6.1 per cent, Hamilton said.

The fact that 20 have already given notice of upcoming rent increases "is . . . rather alarming," said Hamilton. "The practice normally is to wait until the end of the month before sending notice."

Noting that under the new law, landlords could send legal notices as late as the last day in January in order to get rent increases in April, Hamilton said he expected "to see a large number added to this list."

He estimated that "20 to 30 per cent of the tenants in Montgomery County will be affected . . . by rent increases by April 1." There are 570 rental properties in the county and about 200,000 tenants, he said.

Even though the landlord-tenant office is concerned about the number of landlords who already have sent out notices, the County Council member who spearheaded the move to replace the county rent control law with voluntary guidelines said he was pleased by the landlords' responsiveness to the guidelines.

"A lot of tenants were scared that landlords would be sending out increases of 20, per cent," said council member John Menke. "But that's not happening. Not all landlords are asking for increases yet, and a large number are following the guidelines" on the amount of the increases.

The county's new guidelines suggest that rents be raised in accordance with increases in the cost of living, as reflected by the area's inflation index. For the current quarter, that figure is 6.1 per cent.

The landlords are not legally required to limit the amount of their increases, as they were under the law which has now been supplanted. If landlords do not adhere to the guidelines, the landlord-tenant office can examine their books to see if the increase appears unjustified.

The office has no legal authority to take action against the landlords if their increases appear unjustified, but the County Council has warned that if large numbers of landlords start to demand unreasonably large increases, it will consider reinstituting mandatory rent controls.

A few of the rent increases announced last week are as high as 26 per cent, but these are in small buildings that have had unusually low rents until now and whose new rents will still be considerably below the country's average rent of $289, Hamilton said.

A representative of Apartment and Office Building Association of Metropolitan Washington said that she also thought most landlords were responding with restraint.

"I'm really surprised that more of them haven't sent out notices," said Caroline Lewis. "Just about every month of the year, landlords send out rental notices, so there would have been a number of tenants given rent increases, anyway.

But Ruth Lederer, president of the Montgomery County Tenants Association, called the number of announced increases "an inordinate number."

"I did have a feeling (the landlords) would hop on this quickly," she said, "and I'm still praying they're going to stay within the law and within the guidelines."