WASHINGTON — U.S. builders started work on slightly fewer homes in February, but they began preparing for what could be the healthiest spring buying season since the housing bubble burst.

The Commerce Department says builders broke ground on a seasonally adjusted annual rate of 698,000 homes last month. That’s down 1.1 percent from January.

But the government revised up its figures from January. And building permits, a gauge of future construction, jumped 5.1 percent last month to the highest level in more than a year.

Construction of single-family homes, which makes up roughly 70 percent of housing starts, dipped in February to 457,000 after rising for four straight months to an 18-month high. A jump in volatile apartment construction offset the decline.

It can take 12 months for a builder to obtain a permit and construct a single-family home.

A mild winter allowed builders to keep working in most parts of the country. And an improving job market has many slightly more optimistic about home sales this year.

Builders are starting to see some signs of progress. A measure of builder sentiment has risen for five out of the past six months and is now at its highest level in nearly five years. Many builders are seeing more people express interest in buying a home, leading them to believe 2012 could be a turnaround year for the market.