Strange sink/dishwasher drainage issues

September 1, 2008 7:38 AM

Why does my sink only drain when the dishwasher is running?

The sink drains fine for half the day, but then slowly but surely begins to clog. But-- if we run the dishwasher, some time in the middle of the cycle the sink will drain and start working properly. Also, occasionally we'll wake up in the morning and there will be about half an inch of brown water in the sink (no bad smell though, so it's not raw sewage) We're on the 5th floor of a 10 story building. I've already dumped a container of Drano down to no effect. Any idea what's going on?

posted by gwint to home & garden (10 comments total)

You have some sort of weird pressure thing going on in your drain. Consult a plumber.
posted by Inspector.Gadget at 7:43 AM on September 1, 2008

Agreed- the pressurized water coming out of the dishwasher is creating a venturi/atomizer effect that sucks the water down. Probably a good plunging is in order.
posted by gjc at 7:56 AM on September 1, 2008

I had this problem and I cleared it myself using a bent coat hanger to clear out cupfull after cupfull of compressed egg shell bits that I thought my food disposal had annihilated. If you clean it yourself or get a pro in to do the job correctly, make sure to only put things down the drain that are supposed to go down the drain.
posted by Science! at 8:13 AM on September 1, 2008

Get, and learn to use a drain auger, aka a snake.
Best $14 I've spent this year.
posted by Thorzdad at 9:00 AM on September 1, 2008

If you have a garbage disposal, I don't think you can use a snake. I think you need a plumber.
posted by Class Goat at 9:48 AM on September 1, 2008

Sometimes the clog will be where the drain hose from the DW attaches to the P-trap under the sink, that is the first place to examine and isn't too difficult for doing yourself,you will need a bucket to catch the contents of the P-trap.
posted by hortense at 10:15 AM on September 1, 2008

You may need to install an air admittance valve (AAV) if a vacuum build-up is causing your problem.
posted by weapons-grade pandemonium at 10:44 AM on September 1, 2008

If you have a garbage disposal, I don't think you can use a snake.
Sure you can. If there is a clog, it is most likely downstream from the disposer. You simply disconnect the trap running out of the disposer, revealing the drain pipe and run the snake into the system from there. Very easy.
posted by Thorzdad at 11:32 AM on September 1, 2008

Very easy.

Yeah. But very disgusting. I bought and learned how to use a snake for a bathroom drain last year. It was the most disgusting thing I think I have ever done, and that is saying something. In the end, the money I will now have to spend on therapy for what emerged from that drain would have been far better spent on a plumber. You know how much those guys charge? Worth. Every. Penny.
posted by The Bellman at 3:30 PM on September 1, 2008

ya hire a Plumber......a licensed & insured one........depending on your condo rules this most likely is a Assoc. problem not the unit owner.
posted by patnok at 5:27 PM on September 1, 2008