As of late September 2026, after another summer of afternoon downpours in Port St. Lucie, I know the routine in this house by heart: flip on the kitchen light, catch something big and brown sprinting for the baseboard, and start scrubbing counters that were already clean. For years I took every palmetto bug as a grade on my housekeeping.
UF/IFAS Extension, the University of Florida’s research and extension arm, reads it differently. Its fact sheet on the American cockroach, the bug most of us call a palmetto bug, says: “The American cockroach is rarely found in houses; however infestations can occur after heavy rain.”
What UF/IFAS says
This roach lives mainly in basements, sewers, steam tunnels and drainage systems, and UF/IFAS says more than 5,000 have sometimes been found in a single sewer manhole. A separate UF/IFAS guide to household cockroaches puts the kitchen panic plainly: “Outdoor cockroaches do not survive well indoors, and many times people overreact to the presence of these cockroaches.”
Why it shows up anyway
The bugs live outside and wander in looking for food and water or to get away from extreme weather. UF/IFAS traces the routes in: they “migrate into houses and apartments from sewers via the plumbing, and from trees and shrubs located alongside buildings or with branches overhanging roofs.” Heavy rain is the push. UF/IFAS says flooding sends insects and other pests looking for higher, drier ground, and during the day this roach rests close to water pipes, sinks, baths and toilets. That’s why one turns up under a clean sink.
Housekeeping still matters a little. A UF/IFAS county office notes that “Carbohydrates and fats are especially attractive to ants and cockroaches,” so crumbs can give a wanderer a reason to stay. They aren’t what brought it in.
What the spray can gets you
UF/IFAS says “Chemical use alone is the least effective control method,” and that often, getting these outdoor roaches out of the house is all the control you need…