We live on the ground floor and had them last spring and this spring as well. Last year we were the only people we knew who had ants. This year, it seems like everyone has them, including those on the third floor. There's not much you can do, honestly. They burrow from the outside in, so if you see bits of dust that looks like pepper, that's from the ants. It seems to be worse this year, but I'm hoping they will disappear around summer like they did last year.
I looked outside under my back porch today and saw a HUGE ant hill. No wonder there are so many of them this year.