"I had a couple of buyers who were supposed to close just prior to April 30 and they delayed their closing until just after May 1 to get the state tax credit," she said. "They also qualified for the federal credit. In talking to my lenders, a lot of people were doing that."

California has extended its $10,000 tax credit for first-time homebuyers and for those purchasing new homes. The $8,000 federal incentive ended April 30.

Moving forward, Goddard expects sales to pick up.

"We should see the pace of closed sales edge up in May and June as these tax-incentivized transactions close," he said.

Home sales in California dipped below the 500,000-unit level for the first time in 19 months, he said, because of supply issues. The demand for "attractive foreclosed properties" well exceeds the number of properties on the market, according to Goddard.

Still, mortgage interest rates continue to hover near historic lows, and many buyers are out in force to take advantage of the combination of low interest rates and affordably priced homes.

"It's an ideal time for many families to purchase their first home even though they may face stiff competition," Goddard said.

Mueller said many potential first-time buyers are putting in offers on homes, only to be outbid by others.

"There are still a lot of foreclosure properties, but there are hundreds if not thousands of buyers out there and that is keeping prices more firm," she said.

Other San Gabriel Valley cities weathered significant price drops, including Walnut, which saw its median price fall 15.3 percent in April to $520,000 compared with $614,000 a year earlier.

La Verne's median price dropped 12.6 percent to $413,000, while Glendora was down 7.7 percent.

Appleton-Young said prices will continue to stabilize or increase because buyer demand far exceeds the number of foreclosed homes that are coming onto the market.

"There is no doubt that the state and federal tax credits have provided a sense of urgency for buyers, so we expect the market to pull back a little when that's gone," she said. "But we don't expect the market to derail. I think it will continue to have momentum."