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Help Needed with Clogged Air Vent Drain Pipe and ? on Dishwasher Drain Pipe Answered

I need help and learning how to remove, de-clog, etc.

The picture is my kitchen sink drain area.  I have two-sink with the right side having a garbage disposal, with connecting pipes leading out.  But then, I have another pipe leading out in the same direction, but it serving as an air vent pipe.  There's a cooper pipe leading up and into the air vent pipe.

Prior to taking the picture, my dishwasher's drainage pipe was connected to the bottom of the cooper pipe.  Well, last night I've noticed my sinks were clogged, I ran the garbage disposal, and then the a gush of garbage water came out of the under sink cabinet.

Well, after a lot of cleaning, this morning I removed the drainage pipe from the sinks, and noticed that my air vent pipe was gushing out the garbage water.

After searching the internet, it's rare to have a clogged air vent, but at the same time, no one seems to install the dishwasher drainage pipe into the air vent pipe.

So my questions are:
1) Should my dishwasher drainage pipe be connected to the upper part of the garbage disposal?  (You can see there's a fitting on the disposal right above the white PVC pipe leading out of the disposal.)

2) Why would they (the original builders) install the dishwasher drain pipe into the air vent pipe?

3) Most importantly, how do I go about in unclogging the air vent pipe?  (It's all bonded together versus having a washers and nuts or a threaded union.)

4) Any answers and questions that I don't know what to ask?  Insights/suggestions?

Please and thank you.




3 years ago

Either get a plumber to fix it or take it all apart, clean it properly and connect the dishwasher the right way.
By the way: using a sink as a waste disposal unit is what brings all the rats in the big cities, just something for people being too lazy ;)


Reply 3 years ago

Well, after using a plunger and a rubber bladder, I realised that the clog was further down the pipes (much further than what my auger would reach). So, a coupon and $270 later, it was fixed.

What I thought was an air vent pipe, is actually just an addition drainage pipe. The plumber said that it was an useless install from the contractor, and that my dishwasher drainage pipe could simply attached to the garbage disposal.

He had used a powered snake to reach down into the pipes.

Case closed :)

Thanks Downunder35m, for your assistance!


Reply 3 years ago

Yes, rats :) When you say take it all part, I'm assuming the plumbing under the sink. But are you also saying the plumbing that goes into the wall? Because if so, then I think the plumber is in my future...


Reply 3 years ago

Depends on where the block is.
In some cases you can be quite lucky with compressed air - either pump or little compressor.
You can get the plastic plunger style pumps for a few bucks at the hardware store - they do a much better job than the rubber ones but for severe cases you might want to invest another 10 bucks for these spring cleaners with a hook at the end.
Put them in, twist them a few times, pull back - keep doing in until all the goo is out and the water runs again.
Usually all the crap starts with oil and grease going hard in the plumbing, so if you are really lucky a big pot of boiling water will help you.