Healthy places Environmental health hazards West Nile virus How to protect against WNV Eliminating mosquito breeding grounds

Eliminating mosquito breeding grounds

The best way to control mosquitoes around your home is to get rid of places they breed.

Standing water

  • Don’t allow any outside water to stand for more than seven days.
  • Cover rainwater barrels with mesh or screen.
  • Drill holes in the bottom of any unused containers so water can’t collect.
  • Remove or drain standing water from bird baths, discarded tires, flower pots, wheelbarrows, barrels or tin cans that are left outdoors.

Swimming or wading pools

  • Immediately remove any water that collects on pool covers. Use a shop vacuum or other submersible pump to remove the standing water. For an above ground pool, siphon off the water using a hose. Someone at a hardware store can help you make an inexpensive siphon and explain how to use it.
  • Make sure the pool’s pump is circulating water properly.
  • Turn over wading pools when not in use.
  • A larvicide product for domestic use containing Bti (Bacillus thuringiensis israelensis) can be purchased at hardware stores. Public Health encourages homeowners to remove the standing water rather than use a larvicide product. If you do use a larvicide, we recommend the product not be applied to the pool cover within two days prior of opening the pool. Please note: Product label instructions must be followed. Larvicide cannot be applied to catch basins or other waters that can drain off your private property.

Eaves and drains

  • Clear leaves and twigs from gutter, storm and roof gutters throughout the summer.
  • Make sure that drainage ditches are not clogged.
  • Check flat roofs frequently for any standing water.


Yard and lawn

  • Immediately throw away raked leaves and other decaying items such as apples or berries that fall from trees. If they aren’t being composted, place them in a closed container until you can dispose of them.
  • Turn over compost piles on a regular basis.
  • Fill in any low depression areas in lawns.
  • Remove areas such as dense shrubbery where mosquitoes breed and rest.
  • Let your neighbours know about potential mosquito breeding grounds on their property.

Inside your home

  • Make sure door and window screens fit tightly and do not have holes.
  • If there are no screens, keep doors and windows closed from early evening to dawn.

What about wetlands (i.e., swamps, and marshes)?

Wetlands do not pose a threat. Wetlands are systems that perform an integral part in the purification of surface and groundwater. They also maintain a fine balance of biological life that should not be disturbed by the use of pesticides or any other method of control for WNV.