When 12 new Bethesda townhouses, moderately priced by the Montgomery County Office of Housing, brought out 612 would-be purchasers last week, Housing Director Eugene Sieminski had all the proof he needed of the strong demand for lower-priced housing in Montgomery County.

The only problem, for which he also had ample evidence, is that no one is building enough houses to meet the demand.

Withintwo months, another eight townhouses will be available. A few months later there will be seven more. And, if certain zoning permits are granted, within 18 months there maybe be another 45. Altogether, 60 houses will be available in the next two years.

Yet that number is only a fraction of the total number of people - 612 - who queued up outside the Montgomery County Council hearing room last week to sign up for a lottery in which they might win a chance for an interview with the builder. The interview would determine if they qualified for mortgage financing.

Including those who participated in last week's lottery, Sieminski estimates that the mailing list for the "Affordable Homes program," as it is called, now totals 2,500.

In addition, even more people than before are now keeping a vigil for the next batch of moderately priced houses. "A lady called me on Friday and said she had a grand time at the lottery," said Sieminski. "She wanted to know when the next lottery was."

Some of the applicants last week were residents who had watched new developments coming up and calculated that Bethesda Court would have to yield some moderate-cost homes. The homes in Bethesda Court were sold by the county in the lottery for no more than $35,490 - in a county where the average house costs more than $70,000. The adjacent townhouses in the development, with essentially the same floor plans, are selling for between $69,000 and $88,000.

Now Sieminski is receiving calls from people inquiring about the opening of Inverness Knolls in Potomac which could be a year and a half away.

Sieminski said the county has little control over the supply of moderately priced homes. A 1974 law requires builders of 50 or more units to set aside 15 percent of their units as moderately priced homes. So the county must wait for new housing developments, which have been hindered in the past few years by the sewer moratorium and by the recession.

"The purpose of (the 1974 law) was to have moderately priced housing without subsidy," said Peg McRory, housing consultant to the Montgomery County Council. "And no one has serious thoughts of increasing the required amount of moderately priced dwelling units to more than 15 percent. One of our purposes was to show that you could integrate moderately priced dwelling units into the community with regularly priced housing."

The county currently has 250 of the cheap houses in Gaithersburg, Rockville, Damascus, [WORD ILLEGIBLE] and, now Bethesda.

The next offering will be eight three-storey townhouses, each with four bedrooms, in the Watkins Mill development, west of Montgomery Village on Watkins Mill Road. Before any notice of their opening is sent out, Sieminski said, the county will review the program to make certain that it is reaching those for whom it is intended.

For starters, Sieminski thinks, the people whose incomes make them perfect candidates for the moderate houses are either not responding or not finding out about the homes. "We've got to find a way to alert people who can afford the houses about the new openings," he said. He added that most of the people who signed up for the lottery met the income requirements for the program, which are scaled according to household size. But they actually made several thousand dollars below what was necessary to finance the houses.

Sieminski said the county may revise its income requirements. "Do we want to limit the people who can apply for certain townhouses?" Sieminski asked. To curb demand, residents from the District and counties outside Montgomery may be barred from applying for housing, Sieminski said.

Also, the program may give some priority to people who sign up for the mailing list early. "We have to decide whether we will simply not accept people less than 30 days before the drawing," Sieminski said.

Those who did apply last week for Bethesda Court, either with or without sufficient incomes, young (in their 20s and 30s), with a median income of about $13,000. The majority were renters, according to Sieminski, and some were a new crop of househunters beginning to show up statiscally in housing profiles - female-headed households with children.

"Some were women in Bethesda getting divorced and deciding what to do," the housing director said.

One woman at the lottery, recently separated, said she had spotted acquaintances in similar situations at the lottery. "They seem like a good deal for people on a limited income," siad the 40-year-old Bethesda woman who has several children. "It's a way for people to stay in the community where they've lived and where their kids have gone to school. They are good houses for people whom the courts have not been too kind with, in terms of child support."