We have had a terrible problem with drain flies in my apartment the past few...

Asked June 12, 2014, 6:25 PM EDT

We have had a terrible problem with drain flies in my apartment the past few years.Exterminators keep insisting that it is a plumbing problem and the plumbers keep saying they have no idea (though they did fix several drain issues in the building, none of the changes has helped.)We found one area where they were coming up from under a bathtub and the landlord redid the bathroom sealing the slab. They still seem to be getting in easily. (Though it is not as bad in the area of the renovated bathroom.)In some parts of the apartment it looks like they are combing up from under the baseboards on the outside walls.It is worse during the summer then the winter but they are here year round! We have been through multiple exterminators, builders, plumbers...... Repeated applications of bleach inside and outside the apartment, bio-enzyme slime stuff for the drains….. The drains are used frequently.Is there any way to fight these things? (I did see the pages here: http://extension.umd.edu/learn/drain-flies and here http://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/non_HGIC_FS/HG26_fli... ) but I wasn’t able to find anything I could use….Thanks for any information you can provide.

Baltimore County Maryland pest control drain flies

1 Response

We hear your frustration.
Drain flies are usually fairly easy to manage, and you seem to have seen our publications on them detailing that they are normally coming from the slime in the drains. A small part of the publication you listed does mention that drain flies "feed on algae, bacteria, and fungi in the slime film. They may also

breed in areas of sewer leaks, back-ups, dirty garbage cans,
saucers under potted plants, clogged storm drains, and in con-
densate pans under refrigerators and air conditioners. Adult
flies may live up to 2 weeks and total development time from
egg to adult may take 7-28 days. Flies emerge daily once an
infestation is underway"
We would guess that perhaps there is a plumbing leak or clog somewhere down the line, or some other wet area. Has anyone used a moisture meter or otherwise noted areas of leaks or wetness? Any mold issues? Are people in other apartments having the same issues? Sewer back ups/clogs ruled out?
We don't really have other ideas at this point.