Our tub started to fill with water every time I ran the dishwasher or ran water down the kitchen drain. I tried the usual plunger and drain cleaner but to no avail. I finally called Mr. Fix It Inc. the local plumber. A man came out within the next hour or so and checked out the system. It turned out that it was tree roots in the sewer pipe leading form the house to the street. He ran a line with a rooter on it and the problem was solved. Great job!