How do I keep mosquitoes out of my rain barrel?

Another common question/concern I hear from people with rain barrels is about mosquitoes getting into their rain water, breeding and spreading disease, particularly the West Nile Virus.

There are over 150 different species of mosquitoes in the United States. The life cycle of a mosquito (from egg to adult) can take as little as 4 days and as long as one month. An average life cycle is from 10-14 days.

Of course, the best way to keep mosquitoes out of your rain barrel is to have a completely closed system. If mosquitoes can't get to the water's surface, they can't breed. In most cases, this is not practical. If you feed your downspout directly into the top of your rain barrel or rainwater collection system without any type of debris filter in the line, you will end up with leaves, pine needles and all other sorts of mess down in the bottom of the rain barrel. (That is a topic for another discussion.)

The next, non-chemical, way to keep mosquitoes from breeding in your rain barrel is to use some sort of screen separating the water in the rain barrel from outside pests and insects. Simply wrapping the downspout in a piece of window screen before placing it into your barrel will filter debris but will clog easily and become ineffective.

I have seen many different solutions to this problem. I have seen people using a simple piece of window screen with a bungee cord holding it onto the barrel, pool baskets, yard drains and almost anything you can think of that can be used as a filter. These things can get expensive.

The best thing I have found (and use every day on my own rain barrels) is a screened basket. This basket simply drops into a hole cut into the top of the rain barrel. It is suspended above the water level and creates a barrier between the rain water and the mosquitoes.

I don't have any gutter covers on my gutters. The basket I use is large enough that it won't clog during a rain storm, no matter what washes down the downspout. It can also be easily removed from the barrel for cleaning when I see that it has been collecting leaves.

If you are still nervous about mosquitoes getting into the barrel, I would suggest using the basket with a piece of window screen around the bottom of it. The basket is sturdy and will catch the heavy debris while the window screen will act as a backup to the screened basket.

I have also seen products called Mosquito Dunks and Mosquito Bits in the home improvement stores. This is a product that is advertised as safe for plants and fish and creates a floating barrier so that any mosquitoes that find their way to your rain water are not able to breed on the water's surface.

As a final note, I would like to add that, given the average life cycle of a mosquito, it is likely that you will use the water you have collected in your rain barrel faster than any mosquito eggs can hatch and grow to adult mosquitoes. If it is 1-2 weeks between rain storms and you use the water you have collected during the dry periods, you shouldn't experience any problems.

For questions or more information, I can be contacted through my website: www.AtlantaRainBarrels.com