This Summer Prevent Pests by Reducing Moisture Outside of Your Home

By Marcia Anderson

Clogged gutters provide the standing water that mosquitoes need for egg laying and larval growth

Clogged gutters provide the standing water that mosquitoes need for egg laying and larval growth

Like most suburban dwellers, I spent the past few weekends trimming vegetation, mowing the lawn and making sure gutters and other areas around the house were clean of debris and standing water. I soon realized that the mosquito, black fly, and other insect populations were blooming along with the flowers. But where were all of these pests coming from?

Bugs and rodents go wherever there is water. If you have a water leak in or under your house, and the wood stays wet, it will attract pests such as: wood lice, carpenter ants, and termites. Pests that eat wood are particularly interested in moist wood because it is easier for them to chew. They also rely on the moisture in the wood as a source of water. Termites and carpenter ants are known for burrowing through wood and forming nests inside the wood structures. Once holes are made because pests have found wet, weakened spots, rodents may enter the home through those gaps. Have your home’s crawlspaces checked for pests when plumbing problems are detected.

Insects and other small pests need to draw life-sustaining moisture from their surroundings, so they avoid dry places and are attracted to moist areas. If the soil around your house is dry, it’ll be less attractive to insects, spiders, centipedes and other pests.

Buckets provide great habitats for mosquito breeding

Buckets provide great habitats for mosquito breeding

Downspouts and gutters are the first places to look for breeding pests. Termites thrive in the moisture often found around your home’s downspouts. Direct water away from your home by turning the downspouts away from the house and use downspout extensions (splash blocks) to disperse rainwater and prevent soil erosion around the foundation. Also watch for leaks and clogs in your gutters that may eventually lead to water damage. Make sure all other drains, including the air conditioner drain lines, flow away from the home and that the pipes extend at least two feet from the foundation.

I found a few standing water sources on my property.

  • The drainage holes on the bottom of a planter were clogged with leaves and collecting rain water.
  • My grandson’s plastic pail and other play equipment had been forgotten outside and had filled with rainwater and mosquito larvae.
  • One of my sprinkler system’s underground lines was leaking, creating a puddle in the yard.
  • Water was collecting in a cavity in one of our trees.

Everyone should take steps to eliminate places where water collects outdoors, such as: tires, garbage cans, tree holes, buckets, wash tubs, even table umbrella stands, etc. This will not only eliminate mosquito breeding habitats, but also water sources for cockroaches and termites. Empty out any water you find to eliminate this problem.

I also had to remove some mulch that was piled too close to the house and trimmed the plants that were growing too close to the siding.  Mulch traps moisture and should be raked away from windowsills, siding and any other wood. Keep a two-foot pest-free strip around the building by trimming branches, and making sure mulch doesn’t touch the foundation.

Tree cavities provide an unexpected breeding spot for mosquitoes

Tree cavities provide an unexpected breeding spot for mosquitoes

Plants growing against the house will also keep siding damp so trim back bushes and trees. Make sure that the soil is sloped away from the house at least six inches every 10 feet. This will reduce soil dampness near your foundation and keep your basement drier.

Lastly, monitor irrigation systems. Ensure sprinklers are adjusted to spray away from the foundation walls and the house.

Be PestWise! Regular maintenance and sanitation are key components of a smart, sensible and sustainable pest management program. Recognizing the value of pest prevention is an important first step. Preventing the accumulation of moisture outside of your home protects you from pests, saves water, and helps the environment. Visit EPA’s website for more information on controlling pests in and around your home.

About the Author: About the Author: Marcia is with EPA’s Center of Expertise for School IPM in Dallas, Texas. She holds a PhD in Environmental Management from Montclair State University along with degrees in Biology, Environmental Design, Landscape Architecture, and Instruction and Curriculum. Marcia was formerly with the EPA Region 2 Pesticides Program and has been a professor of Earth and Environmental Studies, Geology, and Oceanography at several universities.

Editor's Note: The views expressed here are intended to explain EPA policy. They do not change anyone's rights or obligations. You may share this post. However, please do not change the title or the content, or remove EPA’s identity as the author. If you do make substantive changes, please do not attribute the edited title or content to EPA or the author.

EPA's official web site is Some links on this page may redirect users from the EPA website to specific content on a non-EPA, third-party site. In doing so, EPA is directing you only to the specific content referenced at the time of publication, not to any other content that may appear on the same webpage or elsewhere on the third-party site, or be added at a later date.

EPA is providing this link for informational purposes only. EPA cannot attest to the accuracy of non-EPA information provided by any third-party sites or any other linked site. EPA does not endorse any non-government websites, companies, internet applications or any policies or information expressed therein.