How long do home foreclosures in a antioch neighborhood affect nearby homes?

As long as they are considered comps for your house or bring down the average price per square foot, they will affect your value. That lasts for a maximum of about 4-5 months. The other problem is that new listings fro sale that come on the market often start lower and sell lower after the foreclosure hit because they must appraise and those REOs are often used as comps. Antioch has some recovery to do. If you are not moving soon it should not affect you, but if you need an appraisal get it now while you have other comps that the appraiser can use that are hopefully higher than the REOs.