Food, including the kind you would not think of
Grease film, crumbs in appliance gaps, and residue on the underside of a cabinet shelf all qualify. So do things people rarely consider food.
- Pet food left in bowls overnight
- Cardboard and paper bags — the glue and fiber are edible to roaches
- Grocery bags and delivery boxes stored in a pantry or garage
- Recycling that has not been rinsed
- Soap residue and organic film in drains
Water and humidity
Water is the more urgent need. A slow leak under a sink, condensation on a toilet tank, a damp cabinet base or a mop area that never fully dries can sustain a population indefinitely.
Central Florida's humidity raises the baseline. Poor bathroom ventilation, A/C condensate issues and irrigation against the foundation all add to it.
Plumbing and appliances
Plumbing chases are highways. The gap where a supply line passes through a cabinet base or a wall is rarely sealed, and it connects warm, damp interior voids across a building.
Appliances contribute warmth. Refrigerator motor housings, dishwasher pans and microwave insulation hold heat and are hard to clean, which makes them favored harborage.
Entry points from outside
- Worn door sweeps and visible daylight gaps at thresholds
- Unsealed utility, cable and A/C line penetrations
- Damaged vent screens and open soffits
- Dryer vents that no longer close
- Weep holes and expansion joints
- Dry floor drains that have lost their trap seal
Neighboring units and shared structures
In apartments, condos, duplexes and townhomes, activity can arrive from an adjoining home through shared walls and stacked plumbing. Treatment next door can even temporarily increase what you see, as roaches move away from treated areas.
This is covered in more detail on the apartment cockroach control page.
Outdoor populations and weather
Large roaches live outdoors in mulch, palm debris, tree holes, valve boxes and irrigated landscaping. Heavy rain floods that harborage and pushes them toward buildings; extended dry stretches push them toward indoor moisture.
That is why sightings in a garage or bathroom often spike after a storm without anything having changed inside the house.
Things that get carried in
- Grocery bags, produce boxes and cardboard deliveries
- Secondhand appliances, especially those with motor housings
- Used furniture and electronics
- Moving boxes from a previously affected property
- Items stored in a shared garage or storage unit
What to check first
Start with water, then food storage, then gaps. Look under every sink for dampness, check the toilet base and supply lines, pull the refrigerator, and inspect door sweeps and utility penetrations.
If activity continues after those are addressed, an inspection can identify the species and locate harborage you cannot reach.