Even at the right price, investing in single family houses to put them up for rent is a tough trade:

Investors are moving out of housing. Here’s why

By Diana Olick

July 22 (CNBC) — They swarmed the distressed housing market, buying thousands of foreclosed properties and pushing prices higher faster than anyone expected. Now investors are pulling back, dissuaded by the higher prices they themselves brought about.

“Perhaps the numbers aren’t working out,” said Lawrence Yun, chief economist of the National Association of Realtors, which reported that just 15 percent of June sales were by investors. That is the lowest share since the association began tracking this cohort in October 2008.

Current homeowners are now driving the housing market, as even investor traffic fell in June for the fourth straight month, according to Campbell/Inside Mortgage Finance. That could mean slower sales going forward, as still tight inventory keeps move-up buyers in place. That, and negative home equity.