Looking at how fast homes are selling as measured by the average number of days properties are on the market before they find buyers, is one way to spot a hot housing market. In the Washington area, Ashton Heights-Clarendon in Arlington, Va., with zip code 22201, is the hottest market by far, with an average of only 13 days from listing to contract.

The amount of time metro-area properties stayed on the market dropped in May as inventory shrank and prices jumped upward. Inventory levels have hit the lowest point since 2005 and homes are being snatched up fastest in zip codes located within the Virginia areas of Arlington, Falls Church and Centreville and in Columbia Heights in the District.

The average days on market or DOM in the metro in May was 56 days, a decrease of 18 percent over the same month in 2011.

"By and large, sellers across the region who are pricing their homes at reasonable levels can expect to see purchase offers within weeks and often-times days," said Corey Hart, senior product manager at the RealEstate Business Intelligence Index.

Days on market
May 2012 Metrics
Locale	Zip Code	County	Sales	Median Sold Price	Avg Sold Price	Avg Sold 2011	Avg DOM	Med DOM
ASHTON HEIGHTS/CLARENDON	22201	Arlington	39	" $510,000 "	" $601,367 "	" $577,997 "	13	8
FALLS CHURCH	22043	Fairfax	23	" $458,000 "	" $456,974 "	" $449,630 "	17	11
LORTON	22079	Fairfax	37	" $356,000 "	" $393,481 "	" $397,809 "	19	10
COLUMBIA HTS/MT PLT	20010	DC	23	" $506,000 "	" $585,391 "	" $518,447 "	20	12
SHIRLINGTON	22206	Arlington	42	" $385,925 "	" $370,965 "	" $389,816 "	20	12
CENTREVILLE	20120	Fairfax	60	" $342,500 "	" $348,696 "	" $370,814 "	21	8
ALEXANDRIA	22308	Fairfax	27	" $570,000 "	" $574,952 "	" $643,716 "	21	5
MANASSAS	20109	Prince William	56	" $200,000 "	" $203,008 "	" $165,330 "	24	10
CENTREVILLE	20121	Fairfax	36	" $285,000 "	" $296,815 "	" $329,836 "	24	10
STERLING	20166	Loudoun	10	" $321,000 "	" $399,850 "	" $303,958 "	25	21
Locale	Zip Code	County	Year over Year Change
ASHTON HEIGHTS/CLARENDON	22201	Arlington	Sales	Median Sold Price	Avg Sold Price	Avg DOM	Med DOM
FALLS CHURCH	22043	Fairfax	-11%	4%	4%	-65%	-58%
LORTON	22079	Fairfax	-15%	21%	2%	-67%	-61%
COLUMBIA HTS/MT PLT	20010	DC	-5%	-4%	-1%	-42%	-23%
SHIRLINGTON	22206	Arlington	-44%	1%	13%	-33%	0%
CENTREVILLE	20120	Fairfax	31%	-3%	-5%	-58%	-50%
ALEXANDRIA	22308	Fairfax	15%	4%	-6%	-45%	-43%
MANASSAS	20109	Prince William	42%	2%	-11%	-76%	-86%
CENTREVILLE	20121	Fairfax	27%	46%	23%	-31%	-41%
STERLING	20166	Loudoun	-10%	-10%	-10%	-20%	11%
	-17%	27%	32%	-49%	-50%
Source: MRIS

In the Ashton Heights-Clarendon area, condos, co-ops, and townhouses made up the majority of sales in May, but single-family homes in excess of $1 million waited only seven days for a contract, pushing up the average sales price by 4% to $601,000.

Five of the 10 zip codes with the fastest moving properties, and 13 of the top 25, were located in Fairfax County.

"I can show you homes in Chantilly, Centreville, Herndon, Reston and Vienna that are selling in days for a $100,000 more than last year, said Robyn Burdett of Re/Max Allegiance in Centreville. "However, I have seen homes on the market for 71 days [yet] get numerous offers and go full price."

Hart said some neighborhoods near the new Silver Line metro, including Herndon and Vienna, are seeing half their homes sell in less than five days, levels not seen since the early 2000s.

Homes in the Columbia Heights / Mount Pleasant area sold faster than in any other District zip codes with only 20 days on market. No Maryland zip code cracked the top 25.

"June and July have historically been the months with the shortest average days on market for the region, so if conditions remain as they were in May with low inventory and low interest rates, we're expecting to see figures go even lower across the region," Hart said.