How to What to Do if You See a Cockroach

Prevent a cockroach infestation with these easy, expert-approved tips

If you spot a cockroach, don’t panic! Cockroaches enter a home in search of food, water, and shelter, but there are many ways to get rid of roaches and prevent them from coming back. In this article, we'll help you determine where roaches hide, the signs of infestation, and ways to eliminate them (plus when to call an exterminator).

This article is based on an interview with our MMPC-certified pest control specialist, Kevin Carrillo.

[Edit]Things You Should Know

• To determine if you have an infestation, search for possible hiding spots in your kitchen and bathroom, like under the sinks and cabinets.
• If you find multiple roaches, droppings, or egg cases, call an exterminator ASAP.
• If there aren't any signs of infestation, use glue traps to kill roaches directly, or set up a bait station to eliminate a few random roaches.

[Edit]Steps

[Edit]What should I do if I see a cockroach?

1. If you see one roach, search for hiding spots and signs of infestation. With a single roach, there’s a slim possibility that it wandered in from outside. You don’t have to call an exterminator immediately, but take proactive steps to diagnose the scale of the issue: search for possible hiding areas and look for any signs of infestation (roach droppings, eggs, skin casks). Once you see 2 roaches, you have an infestation—contact an exterminator as soon as possible.^[1]
   
   • Roaches are nocturnal, so you won’t find them when they’re most active. If you see one during the day, get professional help ASAP—it’s usually a sign of overcrowding.^[2]

[Edit]Finding Hidden Roaches

1. Clean out kitchen and bathroom cabinets. Cockroaches thrive in warm, humid environments, so check inside your kitchen and bathroom cabinets for potential hiding spots. Empty all the shelving for the entire room, and carefully scan for any cracks or holes in the cabinetry.^[3]
   
   • Usually, 80-90% of cockroaches reside in the kitchen or bathroom.^[4]
2. Search for cracks and crevices in walls. A cockroach can wedge into an opening that’s only 1 millimeter (0.04 in) to 2 millimeters (0.08 in) thicker than itself, so check if there’s any damage to your walls, window screens, or door frames.^[5]
   
   • When foraging, cockroaches usually gather in corners and travel along the edges of walls, so prioritize the perimeter of your home before inspecting interior walls.^[6]
3. Inspect areas around kitchen appliances. Cockroaches are attracted to heat sources, so look underneath your refrigerator, dishwasher, and oven to check for a possible infestation.^[7]
   
   • Additionally, focus on places that may have food residue like your utensils, toaster, and garbage disposal.

[Edit]Signs of an Infestation

1. Roach droppings{endbold} Cockroach feces look like tiny black specks, similar to scattered coffee grounds, and they’re usually a good indication of the size of the population.^[8]
   
   • Droppings can be found anywhere in your home, but pay extra attention to areas near food sources.
   • If you see droppings, clean them as soon as possible: roach feces can spread disease, attract other roaches, and trigger allergies.^[9]
   • To clean droppings, wear protective gear (gloves, mask), vacuum the droppings, and cover all affected surfaces with a disinfectant.^[10]
2. Egg cases{endbold} Roaches don’t lay eggs one at a time–they lay egg cases. These reddish-brown cases are made of a hard protein, and they look like small, dried out kidney beans, about long.^[11]
   
   • Egg cases typically carry 40 young, and females lay them 1-2 days before hatching.^[12]
   • Search for egg cases around heated appliances such as your oven, fridge, dishwasher, washer, dryer, and water heater.^[13]
   • If you find an egg case, stomp on it, vacuum the pieces, and dispose of it in an outdoor trash can. Then, call an exterminator as soon as possible.^[14]
3. Skin casts{endbold} If you find light brown, cockroach-shaped skins around your home, you may have an infestation. Cockroach nymphs shed their exoskeletons when they reach maturity, which signals a full reproductive cycle within a nest.^[15]
   
4. Musty odor{endbold} If there’s an infestation, you may start to smell a sharp, mildewy odor in your home. This could be coming from live roaches or dead, decaying ones.^[16]
   

[Edit]Getting Rid of Roaches

1. Use glue traps to kill roaches on the spot. Glue traps help determine the size of the problem and indicate the most infested areas of your home. To trap cockroaches, position glue traps in the corners of the room, behind large appliances, and inside cabinets.^[17]
   
   • Cockroaches are often caught within 24 hours of placing the traps, but check them daily to determine where the most insects are located.
   • Discard glue traps every 2-3 days by securing them in a plastic bag placed inside your trash can.^[18]
2. Set up a bait station to eliminate an entire roach nest. Bait stations are small plastic units filled with insecticide; cockroaches enter through small holes to retrieve the bait, then share the bait with others. Position bait stations along walls and appliances, and use roach droppings to help you determine other high traffic areas to place them.^[19]
   
   • Alternatively, purchase gel baits that you can apply under the lip of your countertop or hinges of your cabinet doors.^[20]
3. Apply liquid concentrate to control infestations quickly. Liquid concentrate, or liquid roach deterrent, typically deters roaches for 1-2 weeks. Follow the instructions on the concentrate to dilute it properly, and mop a thin layer of solution to surfaces where you’ve seen the most roaches.^[21]
   
   • Alternatively, use an aerosol can to spray the deterrent into cracks and crevices where roaches enjoy hiding.
   • Since liquid concentrate contains toxic chemicals, avoid using it near children and pets.
4. Kill cockroaches directly with insecticide spray. For a quick and easy solution, use an insecticide that’s specifically formulated for cockroaches. Spray it in any crevices to coat and kill roaches that walk through that area.^[22]
   
   • Insecticide sprays include harmful chemicals, so avoid using them in the kitchen or near children.
   • If you don’t have any spray on hand, mist the cockroaches with rubbing alcohol instead.^[23]
5. Sprinkle pesticide dust to dehydrate and kill roaches. Cockroaches get dehydrated when they walk through pesticide dust, so it’s a great option for long-term treatment. Use a bulb duster to apply a thin layer of pesticide dust into any cracks and crevices, especially underneath sinks, corners of cabinets, and along baseboards.^[24]
   
   • Thin layers of dust are more effective than thick layers, which may clump or cake together.
   • Boric acid is the most common dust treatment, and it’s fairly lower in toxicity than commercial pesticides.^[25]
6. Experiment with essential oils to deter roaches. For a natural insecticide, place a few drops of rosemary oil around the corners of your home. Rosemary oil is highly toxic to cockroaches, so reapply it at least once a week to maintain effectiveness.^[26]
   
   • Alternatively, make an essential oil spray by combining of water with 15 drops of rosemary oil.

[Edit]Prevention Tips

1. Seal any holes and cracks. To prevent roaches from entering your home, use caulk to fill in gaps around your walls, windows, and doors. Make sure to cover areas in walls where pipes pass through, especially in your kitchen and bathroom.^[27]
   
   • If you live in an apartment, make sure to consult your landlord before attempting to repair any gaps yourself.
2. Clean your kitchen frequently. Roaches love fat and grease, so pay extra attention to your backsplash and grease traps. Wipe down kitchen appliances, sweep the floor for crumbs, and ensure there’s no pile up of dirty dishes.^[28]
   
   • Store food in airtight containers, and avoid leaving pet food out.
   • Garbage is the primary food source for most cockroaches, so take the trash out daily.^[29]
3. Eliminate sources of moisture. Cockroaches are in constant search for water, so clean up spills promptly and eliminate any standing water sources. If you have a higher water bill than usual, it may be a sign of a water leak. Check your water meter when no one is home and when they return. If the meter has moved at all, you have a leak.^[30]
   
   • If you find water leaks in your home contact a plumber to treat the issue as soon as possible.^[31]
4. Pick up clutter. Cockroaches easily hitch a ride on deliveries, and cardboard boxes are excellent breeding grounds for roaches. If you have any cardboard boxes in your home, use them quickly or recycle them.^[32]
   
   • Newspapers are common hiding spots for roaches, so avoid piling them inside your home.

[Edit]References

1. ↑ https://ipm.ucanr.edu/PMG/PESTNOTES/pn7467.html
2. ↑ https://ipm.ucanr.edu/PMG/PESTNOTES/pn7467.html
3. ↑ [v161169_b01]. 22 October 2019.
4. ↑ [v161169_b01]. 22 October 2019.
5. ↑ [v161169_b01]. 22 October 2019.
6. ↑ https://ipm.ucanr.edu/PMG/PESTNOTES/pn7467.html
7. ↑ [v161011_b01]. 18 February 2021.
8. ↑ https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/ENTO/ento-528/ENTO-528.pdf
9. ↑ https://www.epa.gov/ipm/cockroaches-and-schools
10. ↑ https://www.centralsan.org/sites/main/files/file-attachments/cockroaches.pdf?1511470413
11. ↑ https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1878&context=extension_curall
12. ↑ https://www.epa.gov/ipm/cockroaches-and-schools
13. ↑ [v161011_b01]. 18 February 2021.
14. ↑ https://extension.umn.edu/insects-infest-homes/cockroaches
15. ↑ http://www.idph.state.il.us/envhealth/pcsaferoach.htm
16. ↑ https://ipm.ucanr.edu/PMG/PESTNOTES/pn7467.html
17. ↑ https://ipm.ucanr.edu/PMG/PESTNOTES/pn7467.html
18. ↑ https://ipm.ucanr.edu/PMG/PESTNOTES/pn7467.html
19. ↑ https://ipm.ucanr.edu/PMG/PESTNOTES/pn7467.html
20. ↑ [v161169_b01]. 22 October 2019.
21. ↑ https://extension.msstate.edu/publications/control-household-insect-pests
22. ↑ https://extension.entm.purdue.edu/publications/E-23/E-23.html
23. ↑ [v161169_b01]. 22 October 2019.
24. ↑ https://extension.entm.purdue.edu/publications/E-23/E-23.html
25. ↑ https://ipm.ucanr.edu/PMG/PESTNOTES/pn7467.html
26. ↑ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5186743
27. ↑ https://extension.psu.edu/german-cockroaches
28. ↑ [v161011_b01]. 18 February 2021.
29. ↑ https://extension.psu.edu/german-cockroaches
30. ↑ https://www.hawaiidws.org/how-to-detect-for-leaks
31. ↑ [v161169_b01]. 22 October 2019.
32. ↑ [v161169_b01]. 22 October 2019.