Check valve in the drain hose leaking

I read your description of what to look for. I re-routed the hose and it is now right under the under side of the cabinet. It seemed to work for a short time then it started to do the same thing. I found out that there is a check valve in the drain hose. This morning I took it off and put a container down to catch the water it is dripping out ever so slowley. It should not leal at all correct?