Kitchen sink/disposal backing up into dishwasher

[trammellclan3]

I have a double sink. Today I was putting some food down the disposal and noticed that it was backing up into the second sink. I put some Liquid Plummer foaming pipesnake in and waited for an hour then flushed w/ hot water. It appeared that it was draining until I turned the disposal on and it started backing up into the second sink again. It finally drained so I was going to run the dishwasher but noticed the nasty water in the bottom, so apparently it is only draining between the disposal, the sinks and the dishwasher but not going anywhere beyond that. We also used a "gas type" do it your self clog remover but that didn't work either. Please help.

[gotmick]

Any idea what it was?

What you use to un-clog it really depends on exactly what is down there, and remember it may have been BEFORE the food that seemed to start this. Grease maybe?

Before spending any more money, try using a regular toilet plunger, and get as much hot water into the mix as possible, even if you have to take some of the cold water out my hand. Five minutes with a plunger has worked for me before with the exact problem.

Good luck!

[LazyPup]

Double sinks and dishwashers can present some additional challenges when attempting to clear a drain clog.

The first problem we encounter is that when we attempt to clear a clog with a plunger in a double sink the force of the plunger is tranferred to the opposite sink via the cross tube and vents out the opposite drain opening therefore there is little if any real pressure applied to the clog. (This explains why your gas type drain opener had no effect). In this case it is necessary to cover the opposite drain with a water tight cover. This can generally be done with a large wet rag stuffed in the drain. If available, I prefer to cover the opposite drain with a second plunger.

When their is a garbage disposal you can often run enough water in the disposal sink to cover the drain opening, then run the disposal motor while plunging the opposite sink. Sometimes the combined force of the disposal discharge and the plunging action will clear the clog.

If you are unable to clear the clog in this manner the next step is to place a bucket under the trap and carefully disconnect the trap. (The bucket must be large enough to contain all the standing water in the sinks). Hopefully once you disconnect the trap you will find the clog in the trap itself and will be able to manually clear it out. If not, it will then be necessary to snake the drain line through the trap adapter on the end of the waste arm coming out of the wall.

You stated that some of the drain water from the sink is backflowing into the dishwasher. This is indicating that the dishwasher drain line is probably not connected in the code approved manner.

The plumbing code requires that the drain line from the dishwasher MUST BE run up as high as possible under the cabinet and secured in place, then dropped down below the disposal and looped back up to the disposal inlet port. The High Loop on the drain line creates a natural trap to prevent water from the sink from backflowing into the dishwasher. (In areas governed by the Uniform Plumbing Code and many local codes require the dishwasher line to be connected to an air gap fitting on top of the counter top, then a second line is run from the air gap down to the disposal inlet or a dishwasher inlet port on the drain lines.)

In this case, before disconnecting the trap if you have someone that can help you, you may have them bend the dishwasher line over double and hold it tight to insure no water can go down the dishwasher line, then either run the disposal while plunging the opposite sink or cover the dishwasher drain tightly while plunging the opposite drain. This may clear your clog making it unnecessary to take the trap apart.

I am attaching an illustration to show the proper method of running the dishwasher drain line when no air gap is required by your local code.

After you get y0ur drain opened up it would be best to let the dishwasher fill with water and pump it out a couple times to clear any drain water that may be in the sump. Then fill the dishwasher again and put a cup of laundry bleach in the dishwasher and let it set about an hour before pumping out to sanitize the sump.

[SSN596]

This is an excellent drawing posted by LazyPup. It clearly shows that if the hose is routed any lower than the high loop shown, there may be a straigh down hill run from the sink into the DW! This is why some codes require the DW air gap. Also, many newer DW are now equipped with a high-loop built into the drain discharge.