In an Anacostia church basement, Donald R. Beach spent his day yesterday listening to homeowners who suspect he is part of a conspiracy to drive up their home prices and chase them out of towm.

About 20 people took advantage of the opportunity to confront Beach, the city's chief real estate tax assessor, who was invited to explain why property in Anacostia -- historically one of the city's most impoverished neighborhoods -- rose in value during the past year at a far faster pace than the citywide average.

Beach spent more than 2 1/2 hours explaining, denying and arguing. But many of the people, as they left, still weren't sure.

"It just seems like it's a losing battle. I still don't understand," said Olivia Brown, who took notes on what Beach said.

Emory West, one of the first to question Beach, asserted that "the District has made a political decision" to make land expensive so it will be developed with costly stuctures.

Beach agreed that D.C. land values are going up, because parcels are selling for higher prices. He insisted, however, that no politics is involved.

Caesar Marshall suggested that the tax assessments somehow were being used as an instrument to turn a profit for speculators. Beach disagreed, saying that the assessors aren't pushing the values up, but that the sales prices are pulling values in the direction.

The average house sale price in Anacostia has almost doubled since 1975 -- from $22,700 then to $44,000 now, Beach said.

The assessments, which lag behind sales by as much as two years, went up an average of 27.9 percent in the past year in Anacostia, according to notices mailed to taxpayers last month. This compared with an 18.6 percent increase citywide.

Why such a disproportionately large increase in Anacostia? Beach told his questioner that Anacostia started from a lower dollar value, so a high percentage value still leaves the neighborhood's values much lower than most of the city. The average home in the city is currently assessed at $56,965; in Anacostia, $29,100.

"Anacostia is a dead housing market," observed John Tetrault, whose modest frame home is across the street from St. Philip's Episcopal Church, where yesterday's meeting was held.

"No, it's not," Beach replied, inviting Tetrault to check the records.

One resident said that didn't justify increases of 205 percent, 185 percent and 140 percent on three vacant lots that, he insisted, should have gone up at the same rate -- and a lower one, at that.It was all a mistake, the resident suggested.

Beach thought it was probably not a mistake. "But if I told you we don't make mistakes, I'd be lying to you," he said.

The city, he said, has only 40 assessors who must make at least a cursory inspection of 149,000 pieces of property every year.The assessors are to go inside the property, when possible.

Marshall, who earlier had sought to link the rising assessments in Anacostia to speculation, said the increases were threatening to force homeowners out of dwellings they had occupied for years. Others voiced agreement.

Rising taxes -- those dollars that citizens actually pay to the city -- might have that effect, but not rising assessment valuations, Beach replied.

The way the city tax law is drafted, the tax rate falls proportionately as the property assessment rises. Thus, each taxpayer's burden will rise only about as fast as the cost of living.

"I go to a lot of these meetings," Beach said, "and you'd be surprised how many people want better government services and they want taxes to go down at the same time."

Emory West nodded in agreement. "Yeah," he said, "that's what we want."