Rising interest rates are putting the brakes on home sales across the country this summer, but the Nashville region has the opposite problem. There are too many buyers and not enough houses for sale.

“People just aren’t putting their homes on the market,” says Andrew Terrell, a Realtor at Pilkerton Realtors in Brentwood.

The reason, it turns out, is the historically low interest rate on mortgage loans – about 3.5 percent – that home buyers enjoyed until the past few weeks. Many homeowners who couldn’t sell their houses during the recession took advantage of that low rate and refinanced. Now they have equity in their home, a lower payment and no reason to sell.

“What’s the motivation?” Terrell asks.

The region has a five-month supply of condominiums, single-family and multi-family homes on the market, Greater Nashville Association of Realtors (GNAR) numbers show. When just single-family homes are counted, the supply dwindles to less than four months. It would take that long to sell every house on the market at the current pace.

Nationally, there was a 5.2-month supply of homes available for purchase at the end of June, National Association of Realtors (NAR) figures show. The association states sales across the country dipped 1.2 percent from May to June. Even so, June 2013 sales were 15.2 percent higher than in June 2012.

A slowdown is not on anyone’s mind in the Nashville region.

“I am so far ahead of myself,” says Re/Max Realtor Judy Rockensock, who is having a record year. “I’m blown away by it.”

Across the region there were 3,151 homes closings in July, a 22.4 percent increase over July 2012 when there were 2,574 closings, according to the GNAR.

The market in Davidson County was even stronger. July sales increased almost 31 percent and the average price rose by 11 percent compared to July 2012. There were 1,469 sales last month for an average price of $231,611. A year ago there were 1,122 sales for an average of $208,577.

Bellevue was one of the city’s hottest neighborhoods. There were 113 sales in the area, a 34.5 percent increase over the 84 closings in July 2012. Last month’s average price was $225,967, 28.8 percent more than the average of $175,479 a year ago, according to a market survey by Chandler Reports.

Sales in Green Hills also surged, but prices were stable. There were 86 sales in the neighborhood, an increase of more than 32 percent over the 65 sales during July 2012. Last month’s average price was $491,493, a 2.4 percent increase over the average of $480,118 a year ago.

“Green Hills is super busy,” says Fridrich & Clark Realtor Richard Bryan. “You can hardly get the sign in the yard before you have two offers.”

In Williamson County, 705 homes were sold in July, 26.1 percent more than July 2012 when there were 559 sales. Last month’s average price was $408,135, nearly 13 percent over the average of $361,935 a year ago.

The Williamson County real estate market has been energized by businesses moving from other locations. Many of their employees buy houses when they arrive.

“We’re seeing a lot of people move into the market. We get calls every day,” Terrell says.

In fast-growing Spring Hill, where GM announced it plans to create up to 1,800 new jobs and add new vehicle lines at its factory, sales were up 37.5 percent and prices were up 15.3 percent over last year. There were 110 sales last month for an average price of $261,319. In July 2012, 80 homes were purchased for an average price of $226,723, according to Chandler Reports’ survey.

Wilson County also enjoyed fast-paced sales. There were 298 sales in July, an increase of 24 percent compared to July 2012 when there were 240 sales. Last month’s average price was $216,538, a 12.5 percent increase compared to the average of $192,503 a year ago.

In suburban Mt. Juliet, 153 homes changed hands in July, 33 percent more than a year ago when 115 houses were sold. Last month’s average price was $238,560, an 11.7 percent increase over last year’s average of $213,652.

In Rutherford County, 531 homes were purchased last month, nearly 16 percent more than in July 2012 when there were 458 transactions. Last month’s average price was $175,972, a 3.2 percent increase over the average price of $170,566 a year ago, according to Chandler Reports.

The market was particularly strong in Smyrna, where Nissan has expanded to produce its all-electric LEAF passenger car. There were 96 sales, a 62.7 percent increase over last year, when there were 59 transactions. Last month’s average price was $164,149, an increase of 8.1 percent over last year’s average of $151,897.