Your town stopped poisoning. Here’s how to keep mice out of your house.
Connecticut towns are taking anticoagulant rodent poison off town property to protect owls, hawks, foxes, pets and kids. You can do the same at home. The lasting fix is the one towns point to as well: find the gaps mice use and seal them.
Four towns, one direction
These are town-property policies. They cover town buildings, parks, grounds and open space, and the contractors who work there. They don’t regulate what you use at home1, and each one allows a limited emergency waiver for a serious infestation.
- April 20, 2026Newtown
The first Connecticut town to stop using first- and second-generation anticoagulant rodenticides on town property, to cut secondary poisoning of birds of prey and other wildlife and potential harm to pets and children.12
- May 21, 2026Southbury
Formally banned second-generation anticoagulant rodenticides on town property, after the town had already stopped using them.3
- October 5, 2026Winchester
Adopted a policy banning routine use of first- and second-generation anticoagulant rodenticides on town property from November 1, with an emphasis on sanitation, removing food and water, and sealing entry points.4
- October 2026Bethel
Stopped using anticoagulant rodenticides on town property and moved to a nontoxic pest control plan, citing owls, hawks, eagles, foxes, coyotes and bobcats.5
Brookfield, New Milford and Monroe were also reported to be considering similar policies.1
Why it matters
Anticoagulant poison stops blood from clotting. A poisoned mouse doesn’t die right away. It gets slow and weak, and that makes it easy prey for an owl, a hawk or a fox, which then takes in the poison too.25 Bait made to be eaten can also end up in the mouths of pets and small children.24
And poison never closes the gap. As long as the hole is open, the next mouse walks right in.
Do it at home
- Find every gap about the width of your finger. If a gap is that wide, a mouse can use it.
- Seal it with stainless steel or galvanized hardware cloth, or exterior-grade metal, set in exterior-grade adhesives and sealants.
- Steel wool and foam are not a fix. Mice chew through foam, and steel wool rusts away.
- No poison, and no traps outside. If mice are already in, use indoor snap traps, only together with sealing.
The 8 entry points
Walk around your house and check each one. Every guide shows where to look and how to seal it for good.
- Roofline, soffit and fasciaMice are climbers. The roof edge is out of sight from the ground, and a small opening up there leads straight into the attic.How to fix it
- Roof returnsA roof return is the small boxed corner where a lower roof runs into a wall. It's often hollow inside, and it can open straight into the eaves.How to fix it
- Where building materials meetBrick, block, stucco and sound siding already keep mice out. The weak spots are the seams where two materials meet.How to fix it
- Pipes and AC line setsWhere the AC lines run through the wall, the hole is almost always bigger than the lines. A gap about the width of your finger is enough for a mouse.How to fix it
- Utility penetrationsEvery line that comes into the house, from power and gas to cable and phone, makes a hole. Those holes are rarely sealed well.How to fix it
- Weep holes and the foundation lineWeep holes are small openings at the bottom of brick and stone walls that let water drain out. They need covering, not sealing.How to fix it
- Garage door corners and bottom sealThe bottom corners of a garage door are where the seal wears, bends or stops short. If you can see daylight there, a mouse can get in.How to fix it
- Doors without sweepsIf you can see light under a door, a mouse can see the way in.How to fix it
Connecticut houses
We’ve been mouse-proofing Connecticut homes since 2005. Older houses here have a few spots worth an extra look.
- Stone foundations
Fieldstone and old mortar joints open up over the years. Look for gaps where stone meets siding or framing.
Where materials meet → - Sill plates
The wood sill that sits on top of the foundation can leave a seam around the whole house. Check it from the outside and from the basement.
The foundation line → - Bulkhead doors
Basement bulkheads warp and settle, leaving gaps at the edges and bottom. If you can see daylight, a mouse can get in.
Door gaps → - Where the lines come in
Oil, gas, power, cable and AC lines all pass through the wall. The hole is almost always bigger than the line.
Utility lines →
Seal it before winter
Fall is when mice move in. As the nights get cold, they look for a warm, dry place with food nearby, and a house is the best one around. Connecticut winters are long, so a mouse that gets in during fall can stay until spring.
The best time to seal is before the first hard frost. If you already hear scratching, it’s not too late. Seal the gaps first, then catch the mice that are already inside with indoor snap traps.
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Mouse-proof my houseSources
- Patch, Newtown, Newtown Becomes First In CT To Ban Rodent Poison On Town Property (April 22, 2026)
- Town of Newtown, Anticoagulant Rodenticide Policy on Municipal Properties (PDF, April 20, 2026)
- The Southbury Record, Southbury Becomes Second Connecticut Town to Ban Rodenticide on Municipal Property (May 22, 2026)
- Town of Winchester, Anticoagulant Rodenticide Policy press release (October 6, 2026)
- Patch, Bethel, Bethel Restricts Use Of Rat Poison On Town Properties (October 12, 2026)