My dishwasher was already installed and part of the kitchen when I purchased the house in 2006. It has worked well until the past year when it started to not drain fully. I checked the drain and nothing blocking; the amount of water left behind varied from zero to about 1.5 inches. No clear pattern - might draine fine for 2 washes and then not drain for 3 washes, etc.,

Now it seems to consistently not drain at all. What is bizarre to me is if I disconnect the outflow drain from the sink's drainage pipe, the dishwasher drains perfectly into a bucket every time. Our sink is a double basin, and both sides drain fine. No problems there.

So as of now, I have a dishwasher that drains into a bucket but will no longer drain into the sink's drainage system.

Not sure if something simple I can fix or should I spend the money to call for a repair or - worst case - maybe its time for a new dishwasher?? Thanks in advance...