The Washington Post (NYSE:WPO) reported Sunday that such businesses as termite inspectors, land surveyors and septic tank repairmen were among those for whom the once-booming housing sector was a boon.

But no more.

Take Radon Control Professionals Inc. The Reston, Va., radon mitigation and abatement company had 12 jobs in a recent week, compared with 30 in the same period last year, said company Vice President James Humphryes.

"We're talking about hundreds of thousands of employees," said Anirban Basu, chief executive of Sage Policy Group, a prominent economic research company.

"There's tremendous pain and uncertainty out there."

At least 10 percent of the District of Columbia-area economic activity is linked to residential real estate, Basu estimated.

In northern Virginia, housing sales were down 47 percent last month compared with January of last year. In Maryland, sales were down 41 percent and 38 percent in the District of Columbia, the newspaper reported.