Drain fly nightmare

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by drainfly, Aug 11, 2006.

  1. drainfly

    drainfly New Member

    Aug 11, 2006
    As my login name and subject line indicate, I've got a major drain fly problem in my downstairs bathroom that has me at my wit's end. Here's a brief history. Any thoughts or suggestions would be greatly appreciated.

    In 9/2005, I purchased a split-level home in Lexington, MA which was built on a concrete slab in 1973. The property abuts wetlands in the backyard. The house is on town sewer and has a 6-zone in-ground sprinkler system which is served by a private well on the property.

    The downstairs bathroom is essentially at ground level. It has a shower with a floor drain, a toilet, a sink and sliding window. There is no ceiling ventilation. The bathroom abuts the laundry room and the utility room.

    -In October of last year, we had 10 straight days of heavy rain, which lead to some flooding at the fringes of my backyard. Nothing infiltrated the house from what I could see.

    -On two consecutive days in December, the toilet in the bathroom overflowed with the contents of our garbage disposal. The kitchen is situated above the bathroom. I had a roto-rooter guy come and he gave us an expensive lesson on why we shouldn't flush baby wipes.

    -Concurrent with this incident, the downstairs bathroom was filled with a mighty sewer stench coupled with the appearance of some drain flies. The plumber changed the wax seal on our toilet and sold us some bio-clean powder to treat the shower floor drain, toilet and sink. The bathroom floor is cheap linoleum and showed evidence of curling up under the radiator. I cut away the curled piece of linoleum and caulked around the base of the radiator and the toilet. Eventually, the odor dissipated.

    -In May, we had another week of non-stop rain, and again the wetlands flooded, with no visible effects to my house.

    -From the spring until now, we have had a raging drain fly problem in the bathroom. The toilet was flushing poorly, so we had it snaked. No fix to the fly problem, though. I treated all the drains with vector bio-5 gel. Nothing. We saw that the floor drain trap holds water, and I was religious about making sure it didn't dry up. I even poured boiling water down the drains several times. I sprayed along the floor and window with gentrol and identified tons of larvae in the seams of the window. I cleaned up the window with bleach and the larvae disappeared there. Nonetheless the flies are everywhere. I've caulked every inch of the bathroom to no avail, and covered the drains and base of the toilet with duct tape. No fix. A plumber tested the radiator and found no evidence that it's leaking.

    -At this point, I had a plumber look again, and he suggested that the shower pan could be leaking and that we tear up the shower floor and break into the slab. I expressed some skepticism, because when we cover the floor drain with tape, the room still fills up with flies. Nonetheless, I filed an insurance claim b/c of the likely expense of tearing up the shower floor.

    -At the same time, I had a bathroom remodeling general contractor look at the bathroom, and the plumber they sent suggested that the problem is due to poor pipe ventilation. He showed that when he flushed the toilet or ran the bathroom sink, the water in the floor drain trap moved up and down. He also suggested that the drain pipe was unusually long (like 18 inches or so). Their suggested remedy was to fix the vent stack and tear up all the plumbing under the floor to fix the system. Understandably, my insurance company balked and wants to send someone to scope the floor drain pipes to look for evidence of a breach.

    -In the meantime, I've noticed outside my bathroom is where the cover to my well is. Moreover, I've found an exposed PVC pipe (about 2 inches in diameter) sticking a few inches out of the ground about 5 feet to the left of the well cap. this pipe is obstructed with rocks. i have no idea where this pipe leads. i checked with my town, and there is no history of there having been a septic system, so i'm thinking maybe it's a stub for the sprinkler system? it appears to go down pretty deep.

    -In summary, my questions are:
    1) is it a reasonable course of action to have the pipes scoped?
    2) is there a reason to believe that poor pipe ventilation is the culprit here? and if so, do i really need to replace the whole stack to remedy the problem?
    3) what could that pipe be sticking out of the ground, and is it a possible culprit?
    4) is it possible that groundwater rose so high after the wetlands flooded that I had seepage under my foundation and that caused a breeding ground for the flies, and that they are entering through cracks that I can't see?

    I'm vacuuming dozens of fly corpses and live flies from my bathroom every day and am at my wit's end? I'm prepared to remodel my bathroom, but I'm leary about tearing up the concrete slab and possibly replacing the whole vent stack.

    What would you recommend????
    Thank you,
    Last edited by a moderator: Jan 16, 2008
  2. Rancher

    Rancher Guest

    Flies appear even if you tape over the floor drain? how about the sink and shower drains and vents?

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  4. drainfly

    drainfly New Member

    Aug 11, 2006
    flies appear if i tape over the shower floor drain, the sink drain and sink vent. i've tested all possible combinations.

    the biggest areas where they concentrate are in the shower (on the side opposite the drain); along the windowsill; and at the base of the sink cabinet against the wall.
  5. prashster

    prashster New Member

    Dec 7, 2005
    Sorry I can't help you. But if you find a solution, please tell me. I have the exact same problem at my company. Drain flies all over the place! YUCK! I notice after weird weather that some of our bathrooms smell, so I suspect the whole thing is a vent issue. Hasn't been severe enough yet to spend too much money on it...
  6. sanaka

    sanaka New Member

    Sep 24, 2005
    Since the well cap is right outside the bathroom, and you've found lots of flies around the window, could they be breeding in the well and coming in around the margins of the window?

    It seems like if you tape over every drain in the bathroom, seal the window, go nuclear with bleach to achieve a momentary state of flylessness, then go into Rambo-hyper-flly-aware mode, you should be able to see in which part of the bathroom they first start accumulating. That should be a good indicator where they are coming from.

  7. aheitkemper

    aheitkemper New Member

    Aug 16, 2006
    College Park Maryland
    tape ofver vents

    You mention Sink vent, sink drain, and shower floor... Did you get the waste over flow for the shower?
  8. geniescience

    geniescience Homeowner

    Nov 27, 2005
    humid summers hot, humid winters cold
    what Sanaka said

    hey wit's end,

    Sounds bad. The flies have propagated. Wherever the source was, is no longer important. The flies are probably able to reproduce anywhere now.

    So I'd do as Sanaka said.

    I had flies that came out of one sink and its overflow. I saw them flying out of the holes. After trying and trying, to send bleach down, to block off the sink and its overflow, to isolate the problem, I still had flies coming out again later within a day or two of opening the tape. So I removed the sink entirely and stubbed the plumbing.

    That was when I figured that the files had at least one secondary breeding place. The flies were not entirely all dead! They were scarcer, but still there.

    Today they are all gone. It took a long time, a rigorous plan, a strict mindset. As far as I know. I am not interested in repeating the experiment for science' sake.

  9. CustomBio

    CustomBio New Member

    Nov 5, 2007
    Drainfly Control

    Drainflies lay their eggs in the grease soap and other gunk that builds up on drain pipes.

    Adding bleach or insecticides may kill the adult flies but generally wont reach the eggs which are buried. Once the eggs hatch, your problem starts again.

    The best way to control drainflies is through prevention.

    A product such as Nullifly or Mop-N-Treat actually removes buildup and thus the breeding grounds for flies.
  10. Mike Swearingen

    Mike Swearingen New Member

    Jan 12, 2005
    Independent Real Estate Broker
    On Albemarle Sound In Northeastern NC
    Any good, non-caustic enzyme-based drain cleaner, such as DrainCare, will dissolve and remove all of that organic gunk inside the pipes and traps that drainflies lay eggs in.
    Hit everything with a rush of warm water, pour in the DrainCare, let it eat that stuff out overnight, and then flush it down with very hot water (I start the flushing of a drain with a kettle of boiling water).
    If there is a lot of gunk build-up, you may have to repeat the process until all of the drain flies are gone.
    Good Luck!
  11. toolaholic

    toolaholic General Contractor Carpenter

    Jul 16, 2005
    Repairing and remodeling homes
    Marin Co. Ca.
    I grew up in The next town , Arlington . There are some very swampy areas.
    The humidity is high. Looking back homes NEVER should have been built there!
    I was a kid laborer there in the50s . We called these homes the polio pits.
    Many water problems. Foundations were below the water level,and not properly waterprofed. French drains in basements would just bring in more swamp water! JUST A DUCKY SITUATION!!
  12. tonykarns

    tonykarns In the Trades

    Jun 5, 2007
    Interior Remodeling
    Foaming agent

    You will never be able to get rid of the drain flies if you dont use a foaming agent which covers ALL of the interior of the pipe. The foaming agents used to get rid of the flies also will break down the materials the flies use to lay their eggs in. The product I use is---InVade Bio Foam and it may take several applications but it works. Keep in mind that it is next to impossible to drown the critters in the egg stage because they can encapsulate themselves in a air bubble under water for 24 hrs!

    Hope this helps you
  13. tempery

    tempery New Member

    Jul 9, 2016
    Be sure, that it's much easier than you think to win fruit flies war. I used invade drain gel. The only way to apply this gel is to pour it into the sewer (4-5 ounces will be enough for the first time though you’d better read the manual first). The gel does not contain any aggressive or dangerous chemicals, but we do advise you to avoid any skin contact with it, so make sure you wear protective gloves. Citrus oil makes up the luring liquid (its smell is rather pleasant) as well as the “natural germs” which destroy everything on their way, be it something organic, spume or odors.
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