Keep Mosquitoes Out of your Rain Barrel

Rain collection devices need to be properly modified and maintained to keep mosquitoes out

Failure to properly prevent mosquitoes can result in increased health risks in your community, and may result in fines up to $1,000 per day in accordance with the California Health and Safety Codes 2000-2067

1. Intake Opening: Always keep the intake opening covered with screen and tightly sealed. A double layer of fine mesh window screen is necessary to keep mosquitoes out. Hoses and downspouts should not feed directly into the rain barrel. An air gap is required so that water must pass through the screen of the intake opening.

2. Decorative Top: Some rain barrels have design elements that can hold water or a rim that allows water to overflow and collect above the screen. Choose a barrel with a smooth top, keep the depressions filled with sand or remove water immediately after rains.

3. Overflow Port: This opening helps keep water from filling above the intake screen but if left open creates an access point for mosquitoes. Securing two layers of fine mesh screen around the opening is recommended.

4. Overflow Port/Valve: Because the outflow valve is an inch or two from the bottom of the barrel, when drained the barrel will still hold water in the bottom below the valve. Securing two layers of fine mesh screen around the opening in recommended as well as keeping the valve closed. The remaining water needs to be removed and the barrel should stay completely dry between rain events.

Mosquitoes need water to lay their eggs and grow. Rain collection devices create a perfect environment for them. Prevent mosquito breeding with these tips:

  • Rain barrels are NOT designed to SAFELY STORE water. Collected rain water should be used right away and barrel must stay dry between rain events.
  • Regularly check the structural integrity of the barrel and quickly repair damaged or worn screens, clogged openings, and loose fitting lids or caps.
  • If you believe mosquitoes are growing in your barrel, remove ALL of the WATER immediately. This will kill any mosquito larvae growing inside.
  • Periodically scrub out the inside of the barrel with a scrub pad and warm, soapy water to remove mosquito eggs that are attached to the inside walls.

Examples of UNSAFE Rain Collection

Modified or decorative tops will hold enough water to breed mosquitoes
Don’t allow water to overflow above the screen or collect in the lid
Large screens and perforated tops will NOT keep mosquitoes out