Snakes in the house: The front door detail that could be welcoming them inside

A worn vinyl strip curls away from the bottom of a front door, leaving a narrow line of daylight above the threshold. It might seem trivial, but it turns out a small snake could pass through that opening, especially into a garage, basement or cool entryway. University of Florida wildlife specialists warn that some small snakes can get through a gap no larger than a pencil.

The gap is worth fixing, but not because it draws snakes to the house. University extension services and state wildlife agencies describe damaged door sweeps and other openings mainly as access points. Food, shelter and favorable temperatures are the more likely draws, and in parts of the country fall is when snakes go looking for all three.

How do snakes get into a house?

Snakes usually get in through gaps at ground level: under doors, around pipes and wiring and through cracks in the foundation.

The University of Florida’s Institute of Food and Agricultural Sciences lists gaps under doors among the openings that let snakes into homes, along with:

• Holes where plumbing and wiring enter the building
• Uncovered attic, roof and plumbing vents
• Cracks in foundations and gaps between a porch or patio and the house
• Pet doors

The Florida guide says snakes looking for a cool place to rest can squeeze under a door, and that rodents in a garage, basement or attic can lure snakes in to hunt.

The Washington Department of Fish and Wildlife’s guidance on living with snakes sorts snakes found indoors into two groups: those that wandered in by accident and are trying to get out, and those that came looking for prey or shelter and would stay if allowed. For a home inspection, the agency’s advice falls into two categories:

• Access points, including poorly fitting doors and weatherstripping, foundation cracks and open garage doors
• Conditions near the building, including rodents and the rock piles, woodpiles and tall grass that shelter them

What attracts snakes to your house?

Rodents, insects and cool, sheltered hiding places draw snakes, especially in fall, when many species look for a place to spend the winter.

The extension guidance identifies specific prey, food sources and cover:

• The University of Missouri Extension advises homeowners to reduce cover by storing firewood away from the foundation, removing brush piles, cutting back shrubs and mowing, and to keep bird feeders away from the house.
• Colorado State University Extension points to rodents, insects and cool, damp shelter. It recommends removing brush and rock piles, keeping shrubbery away from foundations, cutting tall grass, storing grain in tightly sealed containers and cleaning up leftover pet food.

Birdseed draws snakes only indirectly. Seed scattered beneath a feeder can support mice and other small animals, which may then attract snakes. The Washington wildlife agency recommends keeping spilled seed out of rodents’ reach. Pet food left outdoors can create a similar chain of events.

Removing such cover does not guarantee a snake-free property, but it can make the immediate area less suitable.

Timing varies by species, location and weather. The University of Missouri Extension says snakes there are on the move from late August through early October, looking for food, shelter and places to spend the winter. Missouri Extension adds that young of some nonvenomous species, such as western rat snakes and prairie kingsnakes, hatch in late summer and are also on the move. Colorado State says snakes’ search for cool, damp shelter may become more noticeable in fall, when they look for places to hibernate. Florida’s guide, by contrast, says snakes there are most active in spring and summer, and the Washington agency notes that in mild areas snakes may briefly emerge from hibernation to feed and bask during warm spells.

How do you keep snakes out of your house?

Seal openings a quarter inch or larger, keep door sweeps and weatherstripping in good repair and control rodents rather than relying on repellents.

Inspect exterior doors from inside during daylight and look for light around the bottom and sides. U.S. Department of Energy weatherization guidance treats visible daylight around an exterior door as a sign of a poor seal and says a door sweep should seal the gap without interfering with how the door opens and closes. Replace cracked, curled or detached seals. The Florida guide recommends inspecting door sweeps and garage door threshold strips now and then for wear.

Check garage doors, basement windows, crawl-space vents and places where pipes, cables or air-conditioning lines enter the building. Colorado State recommends sealing openings a quarter inch or larger with mortar, caulk, expanding foam or hardware cloth. Cover necessary vents with hardware cloth that does not interfere with ventilation.

The Missouri extension calls late summer and fall a good time to look for entry points. Check again after foundation work, storm damage or the installation of utilities. A separate Missouri Extension guide notes that damaged buildings are more likely to attract snakes because they offer so many ways in. Keep birdseed and pet food in tightly closed containers, remove spilled feed promptly and address signs of rodents. The Florida guide says advertised snake repellents do not work, and Colorado State says the evidence is too thin to recommend them.

The university guidance cited above emphasizes exclusion, rodent control and habitat management. No single treatment can prevent every snake encounter.

What should you do if you find a snake in your house?

Stay calm, keep children and pets away, confine the snake to one room if you can and call a professional if you are not sure whether it is venomous.

If a snake is found inside, keep children and pets away and do not try to handle it by hand. The Missouri extension suggests keeping the snake contained in one room and rolling a towel along the bottom of the door so it cannot slip out. Local animal control, a licensed wildlife removal service or a state wildlife agency can advise on removal.

If you cannot tell whether the snake is venomous, the Florida guide advises photographing it from a safe distance and contacting a professional rather than handling it. Approaching or cornering the animal creates unnecessary risk.

Once the snake is gone, the Missouri extension advises sealing any openings into the home so it does not return. That may be as simple as replacing the worn strip under the front door.

All five fixes from the review are in this version: the lede wording, “mainly as access points,” the birdseed line, and the three rewordings that were too close to the source text.