Industry News

Drain flies: more than drain management

Psychoda drain flies got their name because they commonly breed in floor drains. They can also breed in drip pans underneath refrigerators or air conditioners. Even if breeding takes place in a single drain, these flies can be hard to locate without altering existing construction.  
Occasionally, drain flies start thriving in organic soil underneath a slab when plumbing breaks. Within months to years, thousands of adult flies can appear in houses or ground-floor apartments. When this happens, it’s not enough to pour approved or label-permitting chemicals into the soil or down pipes. Even drilling holes in the slab and attempting a termite-like application won’t solve the problem. The solution requires breaking up the slab and physically removing all the organic debris at least 2 ft. deep. Then, you must replace the area with clean soil and repour a slab after new piping is stalled.

The inspection tools 

 When a pest management professional goes on a drain fly service call, there are certain tools they should have: 
  • Booties to cover your shoes  
  • Latex gloves to protect your hands 
  • Knee pads (expect to do a lot of kneeling) 
  • A screwdriver (Phillips and flat) to loosen screws on floor drains so you can lift them up to inspect 
  • A fly swatter to physically knock out any adult flies, which tend to rest in restrooms and on walls of rooms with drains 
  • A night light and sticky traps to attract emerging adults 
  • This may give customers some peace of mind by seeing them caught 
  • A copy of the fly’s life cycle and picture of the fly so you can better inform the customer what they are dealing with 
  • Labels and SDS sheets on the product you are using 
  • A specimen bottle to collect fly specimens, if they’re not drain flies and you need to identify them 
  • A strong hand lens for insect identification 
  • A strong flashlight to help you see into drains, which will cause the fly larvae to undulate 
  • Plastic cups to place over drains to catch any flies that emerge, which can help verify they are breeding in that drain 
  • Tape to hold the plastic cups in place 
  • Enzyme material approved for drains to destroy the fauna the fly larvae are feeding upon

The actual inspection 

Listen to the customer and ask where they see the flies, how long they have been seeing them and about how many they find in each area daily. Also ask if they experienced any leaks in the last year or so. 
Locations to inspect:
  • All floor drains including in sinks, cabinets, shower stalls, drip pans on appliances and bar sinks 
  • In the toilet tank underneath the cover 
  • Outdoors where air conditioners drip 
  • Sewer traps 
  • Catch basins and French drains 
Simple jobs require simple treatment, but always conduct a detailed inspection using the correct tools. Occasionally, you may have to remove a baseboard or open a wall to find a small leak in vertical piping. 


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