Bugs in the air (vent)

November 3, 2011 12:51 PM

Sink air vent invites buggaboos?

This is the air vent for my sink/dishwasher. We have some sort of small, gnat like hopping flying bug that comes out of this thing and is driving us crazy.

(closer shot)

I showed this picture to the best place in LA for plumbing issues (Lincoln Pipe) and they said they have never seen anything like it. The pipe has a fine thread all the way to the wall, the OD is 1-1/4 inches.

Two questions. A. Where can I find something that is not so absurd looking to cover this thing and B. How best to rid myself of flying, hopping buggaboos?

posted by silsurf to Home & Garden (5 answers total)

Betting you have fruit flies breeding in the years of gunk and cruft built up in that pipe. Get a syringe and inject some strong bleach/water mixture into that vent a few times. That should kill off the eggs. Put out a small shallow dish of vinegar to trap the flies. Put some steel wool or a mesh screen inside the pipe to keep them from getting in there in the future.
posted by cosmicbandito at 1:09 PM on November 3, 2011 [1 favorite]

I am thinking either Phorid flies or drain flies (family Psychodidae). More likely phorid flies if they 'hop'. Cleanliness is next to flylessness.
posted by bolognius maximus at 2:19 PM on November 3, 2011

You could cover the vent with a AAR (Air admittance valve). There is probably one already in the wall or under you sink that has failed and replacing it may help your bug problem.

Do not merely cap the pipe.
posted by Mitheral at 2:32 PM on November 3, 2011

Best answer: I'm with your plumber - if that's really your pipe vent, I have no idea why it's not just venting sewer gas straight into your kitchen (which is why you wouldn't want to seal your sewer vent, but if you're just venting sewer gases straight into your kitchen....

How old is your house and what do the pipes under your sink look like?
posted by Kid Charlemagne at 9:32 PM on November 3, 2011

It isn't the sewer pipe vent. It's an airpipe that allows the water to drain into the sink drain. This is because your dishwasher water has to come up to connect to the drain for your sink. These generally connect to the sink drain above the J trap that blocks sewer gasses from reaching and asphyxiating (or at least nauseating) you. Diagram here.

The Diswasher Air gap - how to clean it and why it's important

It is pretty unusual to come out of the wall like that, but I'm reasonably sure that's what its purpose is. You can try to figure out from under your sink how it's connected. Modern drainpipe is PVC and the dishwasher line is a flexible tubing; you can actually disconnect this fairly easily (in theory by hand) and flush it directly with very hot and/or bleach-infused water (it will just back up into your dishwasher until you run it again). If it's metal pipe, obviously, it will be a bit more difficult, but fittings are still generally pipe-wrench-able.
posted by dhartung at 12:46 AM on November 4, 2011