Q. I have this strange infestation of worms with legs I’ve had in my house this year. They kind of look like millipedes.
What you found are indeed a species of millipedes, locally known as the yellow-banded millipede.
Millipedes live outdoors and are considered beneficial since they feed on decomposing organic matter. Indoors, they can be a nuisance but they don’t do any damage, won’t breed and will die within a day since it’s too dry inside.
To keep millipedes (and other creatures) out of your house, make sure that your weather-stripping around the doors is in good shape. Check at night with a flashlight, one person on each side of the closed door and look for light leaks. Weather-stripping sliding glass doors are more of a challenge, but try the best you can.
This species can crawl through soffit vents, so make sure the screens are in good shape. Seal all cracks and crevices in the walls. They appear to be attracted to porch lights, so turn off lights when not in use.
To discourage millipedes from living close to the house, make sure that mulch is no more than 3-4 inches deep and is at least 2-3 feet away from the foundation of the house. Cap off sprinkler heads that spray water near the foundation of the house since millipedes prefer high-moisture places.
Pesticides are usually unnecessary since it won’t solve this problem and it’s fairly easy to keep millipedes and insects out of the house.