The Rain is Here; Have You Mosquito-Proofed Your Rain Barrel?

Image Credit: CDC
Mosquito larvae

Our winter rains have finally arrived and that rain barrel you invested in is filling up!

But are you sure your rain barrel is safe? Are you sure it won’t turn into a mosquito factory once the weather warms up?

It can happen. Mosquitoes lay their eggs in water and if you don’t mosquito-proof your rain barrel, you could be swimming in mosquito larvae very quickly.

County Vector Control inspectors say they have found rain barrels teeming with mosquitoes, some because they were poorly sealed, others because they were homemade barrels that didn’t have proper screening to keep bugs out.

San Diego County has dozens of mosquito species. Some are just annoying, but others can carry dangerous diseases. That includes our native Culex mosquitoes, which can transmit West Nile virus from infected birds to people. And invasive Aedes mosquitoes that can transmit Zika virus if they first bite an infected person.

So Vector Control has some tips to help you make sure your rain barrel won’t become a mosquito farm. And, while you’re checking your rain barrel, also make sure to check inside and outside your home to find standing water where mosquitoes can breed and dump it out. That’s especially important in the case of the invasive Aedes mosquitoes, which are known for living and breeding very close to people: in backyards, even inside peoples’ homes.

Mosquito-Proofing Your Rain Barrel

Go for the Real Thing
It’s always best to use a container that has been specifically created to be a rain barrel — as opposed to, say, a makeshift trash can — that is designed to keep bugs and debris out.

Use Mosquito-Proof Screening
The mesh on your screening should be same kind you can find on your window screens — to seal openings that could allow mosquitoes into your rain barrel.

Keep Barrel Lids and Connectors Sealed Tight
Make sure your barrel’s lids and connectors are tight to keep out bugs (especially check openings where rain gutters flow into your barrel).

Put “Mosquito Dunks” in Your Barrel
Mosquito dunks are doughnut shaped or granular mosquito larvicides you can buy at retail outlets. They contain Bti, a bacteria that doesn’t hurt fish, people or pets, but when dropped in water sources, it kills mosquito larvae when they eat it.

Check Your Barrel Regularly
Be sure to regularly inspect your rain barrel to get rid of any water that could pool up on the outside and create a place where mosquitoes can breed.

For more information about mosquitoes and how to protect yourself, visit the County Department of Environmental Health’s mosquito Web page.


Gig Conaughton is a communications specialist with the County of San Diego Communications Office. Contact