Re-Using and Re-cycling Water

It’s a fact that mosquitoes need standing water to develop and that they transmit diseases to humans and animals.  It is also a fact that water conservation is extremely important as communities in California face the threat of water shortages caused by drought and waste.  However, we must not forget the responsibility of maintaining an environment that does not harm or effect human health. 

Mosquitoes can be annoying, but most importantly they have the ability to spread diseases like West Nile Virus (WNV).  By following simple mosquito-proofing tips for common water conservation methods, we can help protect the environment and most importantly protect human health.


  • Use a rain barrel with a mosquito-proof screen. This should be fine mesh, 1/16th of an inch, under the lid and covering the overflow hole.
  • Keep your rain barrel lid and all connections sealed.
  • If possible, place your rain barrel on a surface that will soak up water that has overflowed.
  • Keep your rain barrel free of organic materials such as leaves and debris.
  • Remove water that may have pooled on top of the barrel at least 1 or 2 times per week.
  • Consider the use of a downspout diverter to direct water into the barrel. 
  • Inspect on a regular basis to make sure there are no cracks or leaks and that all seals and fittings remain intact.
  • Keep downspouts and gutters clean and free of debris.


  • Cisterns (above and below ground) should be completely enclosed with no openings to the outside.
  • Tightly seal cistern lids and connections.
  • Cover all inlets, outlets and vents with fine mesh screen (1/16th of an inch).
  • Inspect on a regular basis to make sure there are no cracks or leaks and that all seals and fittings remain intact.
  • The area surrounding cisterns should be designed to either divert or absorb excess water from an overflow.
  • The inside of the cistern must be accessible for periodic maintenance as well as inspection by mosquito control personnel.


(BMP’s for mosquito control)

It is important that storm water treatment, storage and re-use features and systems are designed and properly maintained.  Correct design and maintenance minimizes the potential for mosquito production, repeated treatments for mosquito larvae and the possibility for the transmission of mosquito-borne diseases such as WNV.  The following list provides key components that can help minimize mosquito production in storm water recycling systems.


  • Select and maintain proper grade for water conveyance, such as swales, retention features and cross drains.
  • Systems should completely dewater within 72 to 96 hours.
  • Avoid loose fitting rock or rip-rap that may trap water, creating an ideal environment for mosquito production.
  • Systems should be easily accessible for inspection and treatment by mosquito control personnel.


  • Choose appropriate vegetation for the specific project.
  • Native, low growing vegetation is preferred to minimize the potential for mosquito production in storm water treatment and rain water harvesting systems.  This will also allow for efficient mosquito control if necessary.
  • Do not plant cattails or other aquatic plant species that can become invasive, such as creeping water primrose (Ludwigia species), water hyacinth (Eichhornia) and parrot feather (Myriophyllum species).
  • Do not surround rain gardens, swales or retention features with dense vegetation that could hinder access.


  • Develop and adhere to a maintenance plan and schedule.
  • Periodic sediment removal may be necessary to minimize mosquito habitat.
  • Aggressively manage unwanted vegetation.
  • Mow or thin out vegetation regularly to avoid overgrowth, ensure proper system function and accessibility.
  • Keep inlets and outlets serviceable and free of debris.

It is your responsibility to maintain any and all water re-use and recycling systems in a manner that does not result in mosquito production.

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