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benjo 04-12-2011 08:44 PM

Help! Drain fly infestation in my apartment
Hello, and thanks for reading my post.

We live on the 30th floor of a New York City apartment. I have a drain fly infestation, and according to my Superintendant I am the only tenant that has complained.

The flies seem to be based in my master bathroom, but we can not locate the source. Also even more than my bathroom the flies congregate around the windows all over my apartment, in all three bedrooms and the living room by the windows. Every day there are tons of them by the windows, dead and alive.

I have taped over the drains and found nothing. I have poured bleach down the drains many times. The exterminator has poured foam down the drains. I have left cups of oil as someone suggested around the apartment to try to locate the source to no avail. I have had the a/c units checked. The plumber is coming tomorrow to snake the drains. I do not know what to do! I have no idea where they are coming from. This is driving me crazy, we must kill about 50 a day. They are everywhere!

Does anyone have any suggestions at all? Have you heard of photo imaging to find moisture behind the walls? How does a moisture meter work? Will it detect moisture behind the tile in my bathroom? I am not in the business, I am a housewife but I am handy and I am willing to spend money to get rid of these f***kers. I am going bananas here and I am obsessed with getting rid of them.

Thank you.


PAbugman 04-14-2011 07:34 AM

Make sure that you get or have a positive identification of these flies, as knowing what specie they are will lead us in the right direction. Drain flies implies "psychoda". Google this and see if they are one and the same. Have a magnifier handy. Close as many doors in your apt as possible, so as to isolate the flies. This could help determine where they are coming from.
If necessary, take specimens to county agents, agricultural agents, entomologists, etc. Positive ID is paramount in solving small fly problems. If they are psychoda, then there is a chronic moisture source, likely related to sewage, that will become more evident as time goes on. Keep us posted with results, questions, etc.

AllanJ 04-14-2011 08:27 AM

1. Look inside the toilet tank.

2. Get some transparent plastic sheeting. Cut it into convenient shapes and sizes, for example 2 feet by 10 feet and tape it over sections of the room for example along one wall where it meets the floor or along one wall where it meets the ceiling. You will need a strip long enough that the space behind it is closed off at the ends also. Wait a week. See if the flies originate inside the closed off area as evidenced by many being trapped back there. (The plastic sheet is to narrow down on the origin, not in order to trap the flies.) Do two or three areas at a time if space permits adn you have enough plastic sheeting. This is a trial and error process as you move the sheets of plastic around. Don't forget the front of the tub as it meets the floor.

If you are ambitious and have a large enough piece such as a painter's dropcloth. you could go from floor to ceiling, sealing around both side walls, splitting the entire bathroom in half. You can peel back one side to go in and out if you blocked off ths shower and not spoil the test, provided you retape it within a few seconds each time. After you narrow it down, use smaller pieces of plastic within the affected area.

benjo 04-14-2011 12:43 PM

Drain fly infestation
Thank you both very much for your replies. Yes I looked up "psychoda" and this is definitely the type of fly. It was also identified as this by two different exterminators that I have brought in.

Last night I closed the bathroom door, put a towel under the bottom of the door and taped around the door seams. I left the shower light on. I also taped over several small openings in the bathroom, including the sink openings in the front of sink (forget what they are called) and the jacuzzi tub jets and a few holes in the grout.

I walked in this morning and found about 20 flies dead and alive. I was successful in catching about 5 flies in the clear duct tape that I taped around the opening where the toilet pipe enters the wall. The inside of the toilet and the inside of the tank are clear. So in addition the the few flies I caught that were behind the wall trying to make their way out of that little pipe area behind the toilet, there were many others that must have found their way out elsewhere.

The other taped areas were clear.

So now I am assuming that the flies are behind the wall. Does it sound like I have a leak from the pipe behind the toilet? I have a plumber coming back tomorrow morning. The first plumber was clueless and had no idea what to do and the exterminators simply want to spray and leave, they aren't interested in helping me determine the source.

I think the plastic wrap sounds like an excellent idea and I am going to head out now and buy the plastic and more tape. Thank you very much for this brilliant idea. I will keep you posted and thank you so much for the support, it is very helpful to know there are knowledgeable people out there who want to help.


PAbugman 04-14-2011 05:32 PM

I've never serviced large apt buildings such as yours, so I'm not familiar with the utilities and such. The largest we have in our town is 3 stories + basement. When your super says that you're the only one complaining, that may well be true. It very well may be true that tenants that should be complaining are not. This happens in apt bldgs when tenants feel that they are at fault, if they're not paying rent, if they don't want to be seen/heard, etc.

Psychoda mean chronic leaks, often associated with sewage. I've also found them in unused dishwashers, because of stagnant water.

Are there any floor drains in your apt?
Are there any trash chutes near you?
How close are you to the roof (wet insulation)?

Don't bother hiring pest control guys that want to spray and leave. That won't work. The source must be found; in rare occasions there may be more than one source. You will probably need more co-operation from management and neighbors-this could be a stumbling block. Is there a tenant/condo association?

benjo 04-15-2011 09:53 AM

Drain fly update
Today the plumber came back with a probe. The only opening large enough to fit the probe was one of the shower knobs, the knob that controls temperature. He removed the plate and sure enough a bunch of flies flew out as he began his probe. The flies are certainly behind the walls.

He could not see enough with his probe so he is coming back on Tuesday. We will drill holes in the tile near the toilet, shower and jacuzzi tub that are large enough to see what is going on. I gave him permission to knock that bathroom open. I am considering that bathroom done at this point. I will deal with renovating it after this is over. I just don't see anyway around this problem.

I spoke with my insurance company about coverage and they said I am not covered for bug extermination, but will be covered if a leak is found.

The issue with living in an apartment building is you are so reliant on your neighbors. I have already had several leaks from my upstairs neighbors. The worst would be to do all this only to renovate and then have this happen all over again, if it their fault. They have made a lot of changes to their plumbing.

At this point I feel at least some sense of control that I have identified that they are coming from behind the bathroom walls. At least I know we should have an answer by Tuesday of the source of our wet/organic matter that is feeding the drain flies.

I will continue plugging as many holes until then but it is amazing that no matter how much I tape and plug they still find a way out and they are still just as numerous throughout the apartment. This bathroom abuts my master closet and the living room on the other side, so they are probably finding their way out of other holes around the apartment.

Thank you for your support and I will let you know what happens on Tuesday.

AllanJ 04-15-2011 12:14 PM

Is this a wall totally within your apartment or is it a boundary wall with the hall or another unit?

Would you use an odor emitting (as opposed to sticky or one time spray) insecticide that you can place or inject into the wall and then seal it up?

PAbugman 04-15-2011 03:28 PM

You're doing good work benjo, but I'm sorry that you are going thru this. I still suspect a cracked or partially open vertical sewage pipe. Hopefully it won't be your responsibility to fix, as I'm sure it is a pipe commonly used by the bldg.

I suspect that if your pipes that are pressurized were leaking, your downstairs neighbors would be aware of it. A sewage pipe is not under pressure and doesn't always leak if cracked or open a bit.

benjo 04-19-2011 08:45 PM

Drain fly update
So.... the plumber arrived today with drills in hand. We punched large holes in the bathroom tile, maybe 12 inches by 12 inches, by the toilet, shower stall and the tub. There was no sign of moisture or leakage at all, and no gassy fumes or moldy fumes. The plumber put the probe down the shower drain and did see a few down there, so he plugged up the shower, filled up the shower basin and then unplugged so the water flooded down the drain. He did this three times. He felt confident this might help, even though I told him that the flies were coming from behind the wall, not the shower drain.

They taped up the wall holes with plastic but now the flies are more numerous then ever, pouring out of tiny holes I imagine in the plastic that we wrapped the holes we dug up with. I have fly tape hanging everywhere in there.

Tomorrow a contractor is coming over to talk about demolishing the bathroom altogether. The plumber feels he needs to see what is going on under the shower base and also he does not see where the shower pipe trap is. We have not used this bathroom now in about 2 weeks so I doubt there will be any moisture below the shower, even if there was a leak in the base.

I guess the only way to totally visualize what is going on is to completely take down the walls and inspect the pipes and vents.And that is what we are going to have to do. Do you have any other suggestions?

I can't take this, I walk into that bathroom and there are 50-60 flies at any given moment. It is so gross. They are all over the windowsills now as well all over my apartment. I am in fear of them laying eggs in other places in the apartment.

I am becoming very despondent about this. I realize in the scheme of life these are just stupid drain flies, but it is sincerely depressing to live with these bugs in my pretty home and not be able to eliminate them. I really need to get a grip I know.

Any advice is appreciated. Thanks.

benjo 04-19-2011 08:48 PM

one more thing
We went downstairs to the apartment below mine. It had no evidence of leaks from my apartment down to theirs. They did have a few drain flies, maybe 4 or 5, not many. The plumber and exterminator inspected the apartment and don't feel they are the cause, even though the apartment has been unused since November. The exterminator ran the water throughout.

Upstairs neighbors haven't complained of the flies at all.

PAbugman 04-20-2011 05:13 PM

I'm more convinced then ever that they will eventually find a cracked sewage pipe and hopefully much of the cost of what you are going thru will be born by management. Keep us posted, I need to know the outcome.

benjo 04-21-2011 01:06 PM

Thanks PABugman! Really good to know that there is support out there. My contractor arrived today with his probe. He looked in the holes that the plumber made yesterday. He came to the same conclusion as me, that there is activity most likely behind the shower pipes or under the shower. He noticed that my shower base is plastic and not connected properly, and commented that a plastic shower base is not supposed to be in a large apartment building. He said there was definitely a bad seal for this base and water could have leaked under the base. He noted that my floor tiles near the shower door are darker in color than the rest of the tile, indicating they could be wet underneath. I mentioned that they could be darker because normally there is a towel there. He agreed but felt it was still worth noting.

He agreed with you that it could be a tiny hole in the sewage line, or possibly a crack in a vent. The bugs were pouring out of every hole that he re-opened today, dead and alive (removed the plastic and tape) so he was able to see that the flies are definitely behind the wall. But when he looked down the shower drain a few flew out of there as well. He also did not see a shower trap, even after probing 3 feet down. But he felt I must have a trap farther down because otherwise we might have an odor. There is no odor. He suggested that perhaps the vent line is in front of the trap which could be causing the problem.

He is coming back on Tuesday to begin to demo the shower. We are going to start with the shower before removing the rest of the bathroom, to try to eliminate extra costs. I felt that I was in good hands today, so that is reassuring.

I will let you know how it goes on Tuesday after the shower walls are removed.

Thank you again for the support.


amyevans 05-11-2011 10:29 AM

I feel for you, it sounds awful.

I seem to have afew weird bug problems in my bathroom, including some flys which now I'm thinking could be drain flys. However the problem is nothing on the scale of yours.

One of the bugs in my bathroom I have no idea what it is, I've searched all over the place and simply can't figure it out.

Really hope you sort it, I don't think I could cope at all if my problem escalated to that level.

Best, best, best of luck.

PAbugman 05-11-2011 06:47 PM

Hello Benjo: Any updates (hopefully progress) for us? Thanks.

benjo 05-12-2011 06:30 PM

My drain fly update
Unfortunately I only have bad news. I have ripped my master bathroom apart from top to bottom and we have found nothing. The pipes are fine. The drain flies slowed down for a while and I was praying that perhaps the wet spot had dried up as we stopped using that bathroom about a month ago. But then a few days ago a new batch must have hatched because I woke up to maybe 100 flies throughout the apartment once again. Again settling mostly by the windowsills. They are indeed flying through the master bath but I think it is just a checkpoint on their way out from wherever they are originating. Because that room is sealed off now with the door and then plastic taped all around, so there is no way that 100 flies got through that plastic. They are making their way out from all directions. I am guessing that perhaps we found so many in there because that bathroom a) had moisture and b) had many openings to escape from behind the wall ie from the holes where the plumbing fixtures are.

I am extremely stressed about this and extremely upset. I have a beautiful and clean apartment, I have put so much time and effort into creating my home and now this. UGH!

I checked in with my neighbor down the hall yesterday to see if she had any flies. She is the only other apartment on my floor. She said she had a few but only in her living room (which doesn't even abut my apartment). Her housekeeper said she has seen them, but it doesn't seem to be a nuisance to them at this point. She said she hadn't really thought about them since there weren't that many.

I am amazed by how many end up by the windows and especially fall below the cushions that are on each windowseat. They are behind all of the pillows on these windowseats as well. I will have to take pictures to explain. I can't even decide a direction because they are in my room and kids room which are all the way east and the livingroom which is all the way on the opposite side of the apartment.

Now that the master bathroom is open I think I will try to see if I can somehow snake a camera through the drop ceiling to see if I can see anything. do you think something like this exists? A way to snake a probe through a drop ceiling for many feet?

The only thing I can think of is that above my livingroom is a terrace belonging to my upstairs neighbors. Perhaps there is a drain up there that has accumulated organic matter, and perhaps there is a leak making it's way into my apartment. But I would assume if there was a leak that I would see it on my ceiling and I see nothing.

Do you think a bug bomb would kill them? Would a bomb kill the larvae? We go away for the summer and my husband suggested we just bomb the interior of the drop ceiling for a week straight to catch them as they emerge from the larvae. I am not even sure if this will work or if it is worth the toxic fumes that it will give off, not to mention coating my furniture and walls.

Do you think heating up the apartment could help? I've heard this is done for bedbugs but don't know if this would kill larvae either. Bottom line is I just don't have any idea what to do or where to turn.

If I don't have any apparent leaks would a moisture meter do any good? Would thermal imaging?

I don't know what to do and I am really desperate. I am focusing so hard on this that I actually dream about the darn things, I have dreamed about researching them on the internet! I am obsessed!

Another thought I had is to tape off all of the light fixtures throughout the paartment to see if they are making their way out from the little holes by the overhead lights. Perhaps that will at least give me an idea of where in the apartment they may be originating, which direction.

Any advice is appreciated. Thank you very much for letting me vent and babble.

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