Small flies, and drains, and cleaning…Oh my!


A typical commercial kitchen is a busy place with lots of activity. Prepping, cooking, plating, washing dishes, occasional food spills, and plenty of foot traffic. In the normal course of activity, there is dirt, debris, and residue left behind.

Kitchen staff or hired cleaning crews can do a good job at cleaning the floors, but there’s one area that’s often overlooked. When your team goes about its daily or nightly cleaning routine, how often do they address the floor drains?

Floor drains often serve as a catch-all for many drain functions within a kitchen, collecting any liquids present on the floor, and serving as drainage points for sinks and beverage lines. More quickly than you might imagine, floor drains can accumulate dirt, debris, grease, and organic matter, leading to a slimy buildup along the edges, walls, and cover of the drain, and sometimes even to the pipes below the floor drain.

This can create a multitude of problems in kitchens including:

  • Foul odors that can permeate through the kitchen and even into dining areas
  • Buildup in drains can attract and create a breeding ground for pests, such as small flies
  • Drain line buildup can reach a point where sinks do not drain properly
  • Drain line backups can disrupt business, and in severe cases, be cause for closure
  • Backups can result in additional charges for emergency plumbing costs

In short, caring for your drains is a critical part of your cleaning and sanitation program. When neglected, their impacts can ripple through your kitchen and foodservice operation.

Where do small fly problems start?

Drains with slimy buildup can attract pests problems that exist in other areas of the kitchen, particularly small flies – what most people commonly call fruit or vinegar flies. These pests can be an annoyance to staff, cause food contamination concerns, and even be visible to customers, turning them off.

Small fly issues often develop away from drains. In kitchens, these areas are usually hot spots:

  • Underneath and behind equipment, especially those where it is difficult to clean
  • In food storage areas, particularly areas with produce, such as potatoes or onions
  • In or around beverage fountains or service areas, such as under drip trays or in drain line bundles from these machines
  • In voids around dishwashers and tray conveyors
  • Along the base of walls where the baseboard isn’t sealed or there is a crack at the floor/wall juncture that allows debris to accumulate

Once existing small flies find a drain, they can lay eggs in the build-up or slime, and the problem can multiply.

You can reduce small fly problems in your kitchen with daily thorough cleaning and sanitation practices. Download Rentokil Steritech’s 40-point cleaning checklist to target and reduce small fly activity.

The do’s and do not’s of keeping floor drains and drain lines clean

Keeping floor drains clean isn’t as hard as it may seem – there are a number of simple solutions that can be implemented. There are also some things that you should not do to maintain the health of your drains.

  • Include drain cleaning in your routine cleaning practices; use a stiff drain cleaning brush with a splash guard to avoid sending potentially dangerous pathogens that can live in drains, such as Listeria monocytogenes, airborne.  
  • As part of drain cleaning, make sure that the drain cover is also thoroughly scrubbed along the sides and underneath to remove any buildup.
  • Before rinsing dirty dishes/pots/pans for the dishwasher, scrape them well and then rinse with cold water. This helps keep any remaining grease solid so it can travel through drain lines more easily.
  • Use an automated drain line injection system to reduce the amount of grease in the main drain line below sinks. Rentokil Steritech has a battery-operated system available, and it can be serviced during your regular pest control service.
  • Do not use harsh chemicals, which can damage pipes and be harmful to the environment.
  • Do not pour bleach down the drains – bleach does not remove any breeding sites and only masks odors temporarily
  • Drain cleaning products such as enzymes or emulsifiers will only temporarily liquefy grease and move it down the line where it will eventually re-solidify.  Enzymes do not digest grease and, therefore do not eliminate the problem.
  • Use a bacteria-based cleaning product in your day to day cleaning practices; these products actually digest organic matter and grease. Rentokil Steritech has a number of products that can be used for spot cleaning or in your mop water, which can be dumped down the floor drain after use and help keep it free-flowing.


With small investments in the right tools and a little bit of elbow grease, you and your team can keep your drain lines free-flowing and keep pests such as small flies away out of your kitchen.

If your staff doesn’t have the bandwidth for drain cleaning, ask your Rentokil Steritech Specialist about options or call 800.488.9495. We will be happy to discuss programs and tools available to help you with drain line maintenance and small fly problem resolution.

For additional tips on dealing with small fly issues, download Rentokil Steritech’s Tips for the prevention of small flies sheet.


Leave a Reply



Contact the experts


Fill out your details and we will call you back