Tight inventory – a dearth of homes for sale – is driving bidding wars throughout the Bay Area, sending prices up and leaving scores of disappointed would-be buyers. Homes that do hit the market sell within days.

So few homes are listed for sale that agents are resurrecting old ways of drumming up business – going door to door, leaving cards and flyers and writing personal letters, asking owners if they’re interested in selling. Social networking and e-mail blasts are being used to increase inventory as well.

“People are going old-school, farming their territory,” said Lynda DiVito, an agent with Redfin in the East Bay, using real estate agent slang for canvassing neighborhoods.

While tight inventory is a national trend, it’s especially pronounced in the Bay Area.

Alameda County, for instance, had 949 homes for sale in February, down 64 percent from the 2,617 on the market at the same time last year, according to data from Realtor.com, the listings website of the National Association of Realtors. Contra Costa County had 899, down 58 percent from 2,152 in February 2012.

“Those are striking reductions in inventory,” said Errol Samuelson, president of Realtor.com.

While inventory numbers did tick up slightly from January to February, that was a normal seasonal change, not an indication of the logjam loosening.

“After seasonal adjustments, inventory is still falling; the underlying trend is still downward,” said Jed Kolko, chief economist with real estate site Trulia.com.

However, he thinks the rate of decline is slowing.

“Inventory tends to fall the most sharply after prices bottom, as no one wants to sell at the bottom, they just want to buy,” he said. Trulia shows that Bay Area prices bottomed more than a year ago.

Price a factor

Sellers remain reluctant and elusive for several reasons. Those who are still underwater – owing more than their house is worth – have the obvious impediment of not wanting to do a short sale.

But many others “feel underwater based on the price they paid,” Samuelson said. That is, someone who paid $700,000 for a home in 2007 won’t feel good about selling it for $625,000 right now, even though the sale would cover their remaining mortgage.

Some potential sellers, seeing prices surge, are hoping to hold out for more. Others who might want to move up to a bigger house fear that the market frenzy means they won’t be able to find or afford anything else.

Now that it’s spring, the busiest real estate season, more homes should start hitting the market. But many agents have been taking matters into their own hands, making pitches directly to potential sellers about why it’s time to get off the fence.

Although there are numerous online sites to track homes for sale, “the way the market is set up now is forcing us to go back to the beginning where (agents) walk up to a door and knock and say, ‘Hi, how are you, my name is … ‘ ” said Adelaida Mejia, a Realtor with Vanguard Property in San Francisco.

Personal touch

She recently worked with a client seeking a home in San Francisco’s Clarendon Heights neighborhood, above Cole Valley. After losing out with bids, she walked the neighborhood with him and identified houses he particularly liked. Mejia looked up the homeowners and wrote personal letters to each, explaining that her client loved the area and was seeking a house there.

“Three weeks later, one person called me back and said ‘We loved your letter, we’d love to talk even though we’re not on the market, come on over,’ ” she said.

Rich and Renee Gimigliano, the homeowners, said they received two or three agent solicitations a week after unsuccessfully trying to sell the house last year, but ignored them because they were form letters.

“Adelaida’s note was different; more personalized,” Rich Gimigliano said. “We were planning to put the house on the market again, but the note just pre-empted that.”

Her client ended up visiting the house, making an all-cash offer and buying it. “It was a really stress-free experience for both” the buyer and seller, she said.

Beating the bushes for sellers is an about-face from just 18 months ago, when the challenge was to find people who wanted to buy.

A corresponding trend is that homes are selling very quickly.

‘Unbelievable’

“The median days on market in Contra Costa is 13 days – that’s unbelievable,” Samuelson said. A year ago it was 33 days.

Redfin has identified another trend it calls “flash sales” – homes that sell within 24 hours of being listed, usually because a buyer swoops in with an offer too good to refuse. Often, those are buyers who have lost other bidding wars and are determined to land a property.

In the past six months, almost 1,000 Bay Area properties went under contract within one day, Redfin said.

“I just had that experience at a house in the Oakland hills,” DiVito said. “I held the brokers’ tour just before putting it on the market. A buyer and agent walked in and offered us our list price in cash on the spot.”

Underscoring how much the market has changed, she said her sellers had tried to sell the house a year ago “and could not move this property, even though they lowered the price three times.”

Same-day offer

The sellers, who were buying a new home and needed to sell quickly, were happy to take the same-day offer since a cash deal meant it couldn’t be derailed by problems with financing or appraisals.

“Flash-sale terms tend to be really good because (buyers) really want to lock down that property quickly,” DiVito said. “They’re more willing to meet the sellers’ needs to scoop it up before anyone else gets it.”

What happens next with inventory is a big question hanging over the real estate recovery.

“My best guess is that you’ll see an orderly return of inventory to the market,” Samuelson said. “I don’t expect that you’ll see the floodgates open and torrents of properties hit the market. But for each percentage point increase in price, there will be some people who for life reasons have wanted to sell for the past five years – their kids moved out, they got divorced – and now feel that the time is right and they have enough equity.”

Tight inventory, fast sales

The number of homes for sale in the six largest Bay Area counties has dropped dramatically compared with a year ago, according to data from the Multiple Listing Service. Correspondingly, the time the homes stay on the market has also dropped.

Source: Realtor.com

Carolyn Said is a San Francisco Chronicle staff writer. E-mail: csaid@sfchronicle.com Twitter: @csaid