One key indicator of the real estate market’s health and competitiveness is inventory, aka the number of houses on the market.

Where it’s dropping, a real estate turnaround seems more likely. Where it’s staying stable or growing, people won’t be hailing the end of the recession.

On that note, I recently received this e-mail from an agent based out of Virginia:

I’m not sure how closely you track the MRIS (multiple listing service) stats, but something very interesting is happening – huge drops in inventory over the past month – DC is down 18%, Arlington down 20%, and Northern VA down 33% — typically we see increases in inventory in spring! Not sure if this is a blip or the recovery taking shape, but a drop in inventory means bad news for buyers and great news for sellers.

I’m not exactly sure which numbers she’s looking at. But the Multiple Regional Information Systems recently released new stats from April 2009 sales in the region, which show some resemblance (the term is used broadly here) to her comments. Here they are for Arlington and Washington D.C., plus links to a few others:

Arlington County Local Market Update:

April Inventory (Condo-Townhouses):

April Inventory (Single Family Homes)

Washington D.C. Local Market Update

April Inventory (Condo-Townhouses):

April Inventory (Single Family Homes)

You can find Alexandria City’s April stats here; Montgomery County’s stats here. Fairfax city’s stats here.