DENVER - It's still a very good time to own an apartment building in Boulder and Broomfield counties.

The counties are those in the metro Denver area with the lowest vacancy rates and highest rents per square foot, according to the latest Denver Metro Apartment Vacancy and Rent Survey, released Thursday by the Apartment Association of Metro Denver and the Colorado Division of Housing.

The fourth-quarter the vacancy rate in the combined Boulder-Broomfield market was 3.7 percent, according to the report, and the average monthly rent was $1,103.61.

The vacancy rate remained unchanged from the third quarter, but bucked the seasonal trend that typically sees more vacancies in the last three months of the year, according to a Division of Housing press release.

Rents rose during the quarter, and Boulder/Broomfield is the metropolitan area's most expensive market based on rent per square foot, which is $1.28. Only in Douglas County is the average monthly rent higher, at $1,186.

The metro area vacancy rate was 4.9 percent, down from 5.4 percent in the same quarter of 2011. The rate is a new low for any fourth quarter since 2000, although it is up from 4.7 percent in the third quarter, which was the lowest rate recorded in any quarter since 2000.

The average rent across the metro area was $979, down from the third quarter's rate of $986.

In the local submarkets, Broomfield had a 6.2 percent vacancy rate and average rents of $1,125. The university area of Boulder had a 0.2 percent rate, with average rents of $922, and the rest of the city had a 1.9 percent vacancy rate, with an average rents of $1,143.