Pest Prevention: A Room-by-Room Plan to Keep Pests Out

Most pests that end up in your house started outside. They come in looking for something to eat, something to drink or a sheltered place to live, and they get in through gaps you may never have noticed. This page gives you a plan to take those things away, room by room and from the outside in, so you spend less time reacting to pests and less money treating them.

What pests need from your home

Every household pest, from ants to mice, needs the same four things. Prevention is the work of denying each one.

Cutting off food and water makes your home less inviting. Sealing entry points keeps out the pests that come looking anyway. You need both.

Start outside: the foundation and yard

Pests reach the walls first, so begin your inspection there.

• Seal utility openings. Check where pipes, wires, the dryer vent, the gas meter and outdoor faucets pass through the siding or foundation. Rodents, ants, spiders and yellowjackets use these gaps.
• Fit door sweeps. Lie on the floor and look for daylight under each exterior door. A 1/16 inch gap lets in insects and spiders, 1/4 inch lets in mice and 1/2 inch lets in rats. Garage doors need a rubber bottom seal.
• Screen the vents. Cover attic, roof and crawlspace vents with 1/4-inch hardware cloth. Add a chimney cap.
• Repair screens on every window and door.
• Caulk cracks around windows, doors and trim.

Then look at the ground around the house:

• Move firewood, lumber and cardboard away from the foundation. Do not store them in a crawlspace.
• Keep mulch thin, about two inches, and pull it back from wood siding and door and window frames.
• Trim plantings near the foundation so vines, ivy and shrubs do not touch the walls.
• Keep wood off the soil. Siding and door and window frames should sit at least six inches above the ground.
• Send water away from the house. Clean gutters, point downspouts away from the walls, grade soil to slope away and adjust sprinklers that soak the foundation.

Use the right patching material. Mice chew through foam, rubber, vinyl, plastic screening and wood. Close gaps larger than 1/4 inch with metal, hardware cloth, concrete or coarse steel wool. Our guide to rodent-proofing your home covers the details.

Room-by-room prevention checklist

Kitchen and pantry

• Store cereal, flour, sugar, grains and pet food in sealed glass or plastic containers.
• Wipe crumbs and spills right away and wash dishes promptly.
• Do not leave pet food or water out overnight.
• Keep trash in a can with a tight lid, empty it often and keep it away from the back door.
• Caulk gaps around cabinets, under the sink and along baseboards.

Bathrooms and laundry

• Fix dripping faucets and leaky toilets.
• Seal gaps where pipes come through walls and floors. Pack them with steel wool and caulk.
• Do not let water sit in trays under appliances.

Basement and crawlspace

• Fix leaks and improve drainage if the space stays damp.
• Keep crawlspace vents clear of debris and plants. A plastic vapor barrier over the soil cuts moisture.
• Store boxes off the floor and away from walls so you can see behind them.

Attic

• Check that vent screens are intact and that there are no gaps at the eaves or roofline.
• Look for droppings, nesting material or chewed insulation a few times a year.

Garage

• Store birdseed, grass seed and pet food in lidded metal or heavy plastic bins.
• Seal the bottom of the garage door and the gap where the slab meets the wall.

Living areas

• Reduce clutter, especially stacks of newspapers, paper bags and cardboard boxes.
• Check boxes, bags and secondhand furniture for pests before you bring them in.
• Empty extra water from houseplant saucers.

Moisture: the problem behind many pest problems

Water draws pests. Standing puddles attract cockroaches, and soil kept wet by leaks and poor drainage draws termites toward the foundation. A dripping pipe or a wet crawlspace can keep a problem going even after treatment. Fix leaks first, keep gutters working and make sure the soil around the house drains away from it. If you have termites, moisture control and breaking wood-to-soil contact are the parts of prevention you can do yourself.

Where to go next

Use these guides to take the next step:

• Integrated pest management explains the step-by-step method professionals use, and how to judge “natural” products honestly.
• The seasonal pest calendar tells you which pests to expect each season and when to do each job.
• Using pesticides safely covers labels, storage and what to do after an accidental exposure.
• Choosing a pest control company gives you the questions to ask before you hire anyone.
• What affects the cost of pest control shows you how to compare quotes fairly.

When to call a professional

Many prevention jobs, like caulking, fitting door sweeps and moving firewood, are weekend DIY work. Consider professional help when an infestation is already established, when the pest damages structures (termites are the classic case), or when the entry points are high on the house or hard to reach. If you hire someone, ask them to find and fix the source of the problem, such as a leaking pipe, before applying any pesticide.