This is what the end of a housing crisis looks like: steadily rising home prices, foreclosure filings at five-year lows, but also millions of vacant foreclosed homes. Years after the housing market crashed, recovering communities from Las Vegas to Fort Lauderdale, Fla., continue to grapple with a glut of vacant properties, which drag down property values, attract vandals and drain public resources. While Prince George’s County escaped the kind of double-digit vacancy rates seen in Nevada and Florida, it had one of the highest percentages of vacant homes of any county in the Washington region. About 7.4 percent of homes in Prince George’s, one of the Maryland jurisdictions hit hardest by foreclosures, were vacant in the 2010 Census, compared with 4.6 percent in Prince William County, another local epicenter of the housing meltdown. No one is sure how many vacant houses there are.