I have been living with drain flies for about 2 months inside my house.

I called an exterminator, he came up and sprayed a bit and he took the flies to a specialist to identify them as moth/drain flies.

They originally started in 1 bathroom, but now they are in every room in my house. I am in a Cape Cod style home built in 1950 and is on a concrete slab.

I have tried drain gel in all drains for a week with no real reduction. Then I cleaned all of the drains with a wire brush and poured in bleach and boiling water. I even covered all of them with some clear tape to see if they are emerging from my drains.. nothing stuck to the tape. Not sure if they are coming up from the drains.

Bleached the refrigerator tray and dried it.

They are in multiple rooms but seem to be most prominent in the kitchen, around the sink area and walls.

They coincidentally began appearing after a washing machine replacement in a room off the kitchen. I even put tape around the washing machine drain pipe and nothing seems to be sticking to it.

I am even noticing them on the outside vinyl siding of my home on warm days.

I cleaned all gutters to rule that out.

These things are driving me insane. Need help finding the breeding site(s)?

I had them myself. The methods you're using aren't going to help, read on!

MOTH OR DRAIN FLIES

Moth or drain flies are small black flies which
Thrive in drain pipes and sewer lines. They need
A lot of moisture to complete their life cycle.
Drain flies do not fly well. They tend to drift
And seem to float along more than fly. Their
Wings are shaped like a leaf of a plant and one
Can see hair like fibers on all parts of their
Body which is why they are also called moth flies.
I have dealt with drain fly infestations in
Many homes which start in the sink or bathroom
Shower. The drain lines which have the most
Activity seem to be the ones most likely to have
An infestation. I have also observed that homes
With septic tanks seem most likely to get them.
I am not sure if there is some kind of build up
Which occurs more with this type of drainage
Or if there is something in the tank which allows
These flies to prosper. Although these homes
Seem more likely to get drain flies, once the
Cycle begins it takes place in the home. I have
Encountered several infestations where the larva
Were found crawling out of shower or bath tub
Drains. The homeowners thought they were some
Kind of leach. In fact, the larva of drain flies
Thrive in a slime buildup which is on virtually
Any drain pipe which is used a lot. This slime
Enables the eggs which are laid to be protected
And sheltered. The eggs and hatching larva
Embed themselves in this slime so they don't wash
Away. The cycle of these flies takes around
A month to complete. Don't waste your time with
bleach or other cleaning solvents. Showers and tubs
Which have ceramic tiles may also supply a moist
Slimy environment in which they can live. Sump
Pumps and wet crawl spaces are other environments
Where I have seen them live. Drain flies can be harder
To control than other small flies. Although
There are several products to kill adults, the
Key is maintaining and minimizing their breeding
Areas. This could prove to be difficult and
Ongoing.
Like most flies, there are several products
Available for their control. Use a "SPACE SPRAY"
For immediate relief of the adults. There are
Several to choose from in the section below.
This will quickly control the adults, but the
Secret to getting rid of them is to use a
Product we sell which removes the slime build
Up on drain pipes. By removing this slime, the
Larva cannot develop. This will stop the cycle.
In the "SURFACE SPRAY" section below, look for
The product called SURVIVORS. This is applied
Down drain pipes and will remove the nest sights
These flies need. You may also use the product
Called PT-CYKICK which is located in the same
Section. It is ideal for treating in cracks and
Crevices where these flies like to lay eggs. Such
Cracks will develop around ceramic tile, windows
And grout joints.

CLICK HERE TO READ MORE: http://www.bugspray.com/catalog/products/page306.html

Tom covered the entire issue. So, I will only add: Make sure you have traps on your fixtures and if you do, make sure they are filled with water, especially floor drains. If there are bathrooms you don't use too much, make sure you run water through the fixture once a week.

Tom, I mentioned in my post that I used "Drain Gel" for just over a week. Is Survivors not the same type of organic eating product?

Is it is possible that I have a crack in my main sewer line going from center of home out to street?

Is there any other not-so-obvious places that I can look? As mentioned in my post, I had a new washer replaced, sits as a stackable below the dryer. I read some posts that these flies can breed under washing machines in the lint. Do you think it is worth ripping out both units out to check and see if there are any signs under the washer? I do not see that many near that area.

Also, I have 2 bathrooms, and although I first noticed them in the upstairs bathroom, I rarely see any in both bathrooms now. It seems that the smallest flies are in all rooms on 1st floor.

This problem is killing me, not to mention the tension it is putting on my marriage. I am willing to do anything to get rid of them but I have no clue if I should try another exterminator or a plumber. Sorry for the rant, I feel totally helpless.

Yes, Drain Gel sounds like the same thing. I wish I could give you some magic potion that would get rid of these pests. I fought mine for months. Like you, nothing seemes to work. I even hung up sticky fly ribbons over my shower and kitchen sink drain to catch the little critters. They aleays returned ,( sigh! ) In the end it wasn't chemicals that got rid of mine. I had my sewer relined and hydrojeted . Since the infestation was in my shower and kitchen sink I sealed off the sink with plastic and closed the shower door. The pressure jet blew most of them up out of the shower drain on the walls where I could kill them with bug spray. I then poured Muriatic Acid down the drains to eat up any larva that remained. I've been Drain Fly free for 6 months now. I really feel for you. I know how frustrating it can get.
Would it be possible for you to call around and get a exterminator that will give you a guarantee that he can rid you of these pests? Have him put it in writing because he'll be coming back a second and third time. I don't think the flies can swim past a trap seal or the toilet trap. Not so sure about the larva. Please keep me in the loop on this as many others will be interested in knowing how you got rid of them. Good luck, Tom

UPDATE: Sewer company came today to do a smoke test. Upon sending smoke down first of two drain vents from roof, no smoke entered home. On the second vent, smoke started shooting out of the base of the first floor toilet around the seal.

I think this is good news and bad news. I am going to have a plumber reset the toilet to the floor. The good news is that I hope this is the source or causing them to breed around this area. The bad news is that I have rarely seen many flies in this particular room of the house and I hope there is no leak deep down below the slab.

Many of the small flies seem to be originating from my kitchen although it is tough to say exactly since they appear in every room. I have been told that they can appear many feet from a breeding source.

I will update this post as soon as I have the toilet repaired so that it may help the many others who are dealing with finding breeding sources.

The Plumbing Page thanks you for the update. Since I had a infestation myself let me know how you made out. Good luck, Tom

[QUOTE=speedball1;1709153 I then poured Muriatic Acid down the drains to eat up any larva that remained. Tom[/QUOTE]

Ha, gotcha Tom, I thought you were dead set against acids... lol.

Just thought id give you some rib poking. Take care.

Ha, gotcha Tom, I thought you were dead set against acids.... lol.

Just thought id give you some rib poking. Take care.

Hey Lee! If you're ever are infested with drain/sewer flies you're going to use everything, including dynamite, to get rid of them.
Muriatic Acid is nowhere as dangerous as Sulfuric Acid and that's what killed my friend when he used Blast Out in a unvented bath room.

We are definitely on the same page Tom. I was just having some fun. Have a good weekend.

UPDATE: Replaced seal on same toilet and remounted. Did another smoke test and smoke still coming out of base of toilet from both roof vents.

Also did a camera down toilet when off and main line looks clean with no clear cracks or buildup down to street. Also did not notice the presence of any flies in the drain.

Snaked one of drain vents from roof above kitchen sink and must of disrupted cause have seen many more flies lately.

Next steps: Replace toilet on Tuesday, June 2nd with new one. Run a smaller camera through the kitchen sink line to the first floor toilet (only other sewer line in slab).

My guess is that there is a leak in the sewer pipe connecting the kitchen sink to the main T near the downstairs toilet. These flies must be breeding under the cement slab and making their way through construction cracks.

Anticipating a large dig up job. Sewer company claims that these flies must be breeding is stagnant sewer water. I asked if there is a possibility that my main water line is leaking under slab BEFORE it gets to the meter, which would be tough to identify, and he said highly unlikely.

I hope there is an end in sight. Saw the drain fly video on Youtube (YouTube - SEWER DRAIN URINAL FRUIT FLIES FLY ATTACK AND INVADE MY HOME (http://www.youtube.com/watch?v=ZmI6dEFgyT8)) where they had to tunnel under the house (with same setup as mine-slab with radiant heat) and I am going crazy hoping I won't have to deal with this.

UPDATE (Advice appreciated):
Sewer company camera'd kitchen line to toilet and sure enough there was a huge crack (more than 3" wide) right after the elbow. Waste water from the kitchen sink and dishwasher has been emptying under the cement slab for who knows how long?

We decided to excavate from the outside of the home and then tunnel under the footing up under the home to replace cracked pipe from underneath. This was mostly die to the fact that the pipe ran alongside outside edge of home. Going through kitchen would be a nightmare and mess ripping out granite countertops and cabinets. Plus I have radiant copper pipes running through cement slab floor and didn't want to disrupt them.

The good news is that we have dug up and replaced the pipe and the flies have stopped appearing in the home... the bad news is that it appears that the flies still may be breeding in the soil beneath the house. We removed much soil below the leak although there are some small roots that are sticking out from the soil and it appears that larvae are re-growing on the ends. Moisture is leaking off the ends of the roots and some quickly become white which what appears to be larve eggs! There is no pools of water, all water seems to have been absorbed by the ground. This may indicate that the soil still contains the absorption of much of that waste water

I am at a point of not knowing what to do. Do I need to keep removing soil which may have spread laterally from the crack down to the left and right... and toward inside of home? The more soil I remove, the more we are going to have to build back up or support the cement slab since we are essentially removing the rock base and dirt from underneath. Do I back fill with fresh soil now to cover exposed roots and keep what may be contaminated dirt well down into the ground below the warmer surface?

One thing is certain, we are definitely going to hold off closing up the hole until there are no more flies breeding underneath. Thanks in advance for any suggestions on how I can put this nightmare past me.

I posted the video at YouTube - Drain Flies, Rotted Sewer Pipe, Excavation, House Cement Slab (http://www.youtube.com/watch?v=IuhSGj1trtE)
Photos are posted here: Excavation Drain Flies - a set on Flickr (http://tiny.cc/HCdDU)

UPDATE (Advice appreciated):
Sewer company camera'd kitchen line to toilet and sure enough there was a huge crack (more than 3" wide) right after the elbow. Waste water from the kitchen sink and dishwasher has been emptying under the cement slab for who knows how long?

We decided to excavate from the outside of the home and then tunnel under the footing up under the home to replace cracked pipe from underneath. This was mostly die to the fact that the pipe ran alongside outside edge of home. Going through kitchen would be a nightmare and mess ripping out granite countertops and cabinets. Plus I have radiant copper pipes running through cement slab floor and didn't want to disrupt them.

The good news is that we have dug up and replaced the pipe and the flies have stopped appearing in the home... the bad news is that it appears that the flies still may be breeding in the soil beneath the house. We removed much soil below the leak although there are some small roots that are sticking out from the soil and it appears that larvae are re-growing on the ends. Moisture is leaking off the ends of the roots and some quickly become white which what appears to be larve eggs! There is no pools of water, all water seems to have been absorbed by the ground. This may indicate that the soil still contains the absorption of much of that waste water

I am at a point of not knowing what to do. Do I need to keep removing soil which may have spread laterally from the crack down to the left and right... and toward inside of home? The more soil I remove, the more we are going to have to build back up or support the cement slab since we are essentially removing the rock base and dirt from underneath. Do I back fill with fresh soil now to cover exposed roots and keep what may be contaminated dirt well down into the ground below the warmer surface?

One thing is certain, we are definitely going to hold off closing up the hole until there are no more flies breeding underneath. Thanks in advance for any suggestions on how I can put this nightmare past me.

I posted the video at YouTube - Drain Flies, Rotted Sewer Pipe, Excavation, House Cement Slab (http://www.youtube.com/watch?v=IuhSGj1trtE)
Photos are posted here: Excavation Drain Flies - a set on Flickr (http://tiny.cc/HCdDU)