Drain Flies
Drain Flies or Drain Mites are a very small fly that feed on waste matter
within sewers and drains, they can however infest a property given the correct circumstances and no amount of fly spray will
halt the infestation unless you can find their point of ingress or their food source and do something about it. The vast majority
of domestic drainage systems are fairly clean in as much as they are designed to carry waste from one point to another and
there should not be any waste sitting in the system, but due to defective pipe work or partial blockages this can happen providing
a food source for the pests. However drainage systems are also designed so that no matter what occurs below ground these flies
should not have access to your property and sinks, baths, toilets etc are fitted with water traps to prevent smells and pests
from leaving the drainage system and entering your home.
So
if you have an infestation of drain flies within your bathroom there are usually a couple of things happening, firstly waste
matter is building up either within or outside the drainage system allowing the flies to feed and breed, if this is occurring
within the drainage system they are also finding an open vent out of the system and into your property. The life span of these
pests is pretty short but they will lay eggs in your property and before long the next generation are swarming over your bathroom
fixtures and fittings.
Typical Drain Fly Infestation Scenarios
The most common and probably the most disturbing for the home owner is when you have
an internal rest bend at the base of a soil vent pipe or downstairs toilet, the rest bend fractures or becomes displaced and
after every flush a certain amount of water and waste escapes into the sub-floor. The matter builds up and the flies have
a food source they can then access the property above through any small gaps between floor boards or gaps local to skirting
boards.
The above can also occur when small diameter
waste pipes from sinks are suspended from joists in sub floors, if these pipes become disconnected or leak there is enough
food stuff, grease & fat in the water for the flies to feed off. Disused branch lines on drainage systems can often hold
waste matter if the system has blocked or partially blocked at any time, because of its location below ground the waste will
not dry out immediately and this can provide a steady and prolonged food source for the mites. If this disused branch line
runs beneath and extension or conservatory and it has not been capped off properly the flies will find their way into the
property.
Leaking and broken pipe work outside of
the property can also allow the flies to enter the house, a cracked collar at the base of a soil vent pipe or a fractured
gully pot that cannot maintain its water level will allow the flies to surface at ground level, if this occurs local to an
air brick they have access direct into your sub-floor and wall cavity. Restaurants and industrial kitchens can be prone to
this kind of infestation due to the amount of food stuffs that can directly enter the drainage system.
How To Stop Drain Fly Infestation
Its critical that you
find the source of the problem rather than just trying to exterminate each wave of the blighters, they don't tend to move
too far from the point of access so its worth studying there movements , if you have a sub-floor its always worth lifting
a couple of boards and checking for standing water and waste matter. Get the drainage system checked out and cleaned, a drain
camera inspection can also locate any defective pipe work or any disused connections. Once the source of the problem has been
located and dealt with you can get the problem area fumigated to deal with the remainder of the enemy, safe in the knowledge
that they will not return.
