I have a kitchen sink with a disposal fitted beneath. My dishwasher is hooked up to the left of the sink but it keeps leaking from beneath, soaking the floor from below. It has been fixed a couple of times. It is now leaking again. I suspect that the drainage plumbing is incorrect and that the dishwasher is also hooked up wrong. No less than four licensed plumbers have said that it looks fine, however, I can no longer believe them.

In looking up sites that offered dishwasher hookup instructions, it seems that we may be missing the air gap fitting and that the plumbing was not installed properly by the former owner of the house.

Please give me explicit instructions with illustrations so that I can fix the situation and then decide whether to fix this dishwasher once more or buy a new one. I do have a friend with the appropriate tools who can help me.

Thank you.

There is a port directly on the disposal for dishwasher hookup. When using that port, an air gap isn't necessary. It's usually a plug that needs to be removed. Take a look and see what you find.

Not all areas require an airgap. If the dishwasher hose is secured to the underside of the counter top so as to prevent waste water from flowing back into the dishwasher you should be fine. I have the impression that this is a double bowl sink. If the dishwasher was installed prior to the disposal it would be connected to a spur off the tail pipe. This is also fine. The disposal also has a spur for connecting a dishwasher if there is a single bowl. Exactly where is the leak. Does it leak only when the dishwasher is used or anytime that bowl is used. Should be easy to see leak.

Post a picture using go advanced of the leak location

Although when an airgap is not used, you typically route the diswasher drain as high as it will go before entering the drain.

How is your diswasher plumbed?

This site suggests that an airgap is required even with garbage disposers:

http://www.smartplumber.org/garbage.htm

But, having the dishwasher drain go as high as possible may satisfy some codes. In escense, water cannot drain uphill and kitchen waste cannot get into the dishwasher.