Drain flies are coming out of a kitchen sink. I have a disposal in which I ground up orange peels and ice on advice of a plumber. He said my only choice was to have a camera from up on the roof. He did not see the pipes as he was there to repair the toilet. I don't see what I would call a trap. I just see a pipe that is connected to the disposal. It come in at a right angle. I tried all the concoctions on line. I finally am using ammonia and borax. Can it be underneath. I am not seeing any flies there.

How old is the disposal unit? Replacement is not a complicated procedure, and may be helpful. Moth flies (the species most often called "drain fly") normally don't care for disposals. Other species are not so picky. Phorid flies that consume mildew and fungi and fruit flies that feed on decaying vegetable matter would find an old disposal that isn't all that efficient very attractive. With the disposal out, you can check the pipes in case it is moth flies.

[SIZE=3][COLOR=#0000ff][SIZE=3][COLOR=#0000ff]http://lifehacker.com/5826486/how-to-get-rid-of-drain-flies[/COLOR][/SIZE][/COLOR][/SIZE][SIZE=3][COLOR=#0000ff][SIZE=3][COLOR=#0000ff][/COLOR][/SIZE][/COLOR][/SIZE]Click on this link for more information,
Didn't you realize that when you had all those drain flues winging around your house that you've left all the drains in your house open for the flies to get into and lay eggs. Like you I located the source of the infestation, however, In order to prevent them from finding new breading grounds I had to close off,(seal) tall the drains in the house until I had to drain something. Then I sealed them up again. Then I went after them one at a time . I put up fly strips over the kitchen sink and any place I could se the little critters flying around. It took a month but now I'm clear. The very first thing you must do is find the source, in your case you have already locater the source . I'm no pest expert but I'vebeen infested twice and I do know drain flies. Good luck. Tom