Roaches in an apartment are a different problem from roaches in a house. You share walls, plumbing and sometimes air with your neighbors, so you can keep your kitchen spotless and still have them. The good news is that apartment roaches have been studied more than almost any other pest, in real apartment buildings, and the research is clear about what works and what makes things worse.
Use gel bait, not sprays or bug bombs, and get the whole building involved. Apartment roaches are almost always German cockroaches. NC State researchers found that German cockroaches collected from apartments were about 200 times more resistant to the pyrethroid insecticides in typical foggers than a lab strain, and the foggers failed to kill them. Baits worked.
The steps: identify the roach, put out sticky traps to find where they live, place small dots of gel bait there, seal the gaps around pipes, and tell your landlord in writing. Rutgers researchers found that treating every infested unit in a building cut the number of infested apartments by about 75% in a year.
Step 1: Make Sure It's a German Cockroach
Treatment depends on which roach you have.
| Roach | Looks like | What it means in an apartment |
|---|---|---|
| German cockroach | 1/2 to 5/8 inch, tan, two dark stripes behind the head. Often seen in kitchens and bathrooms | An indoor infestation. It breeds inside your unit or your neighbor's. This is the one this guide is about |
| American cockroach (palmetto bug) | 1.5 to 2 inches, red-brown, pale ring behind the head | Usually wanders in from outside, the sewer line or a crawl space. Common on ground floors after storms |
| Smokybrown cockroach | 1 to 1.5 inches, solid shiny dark brown | Mostly an outdoor roach from trees, mulch and gutters that can move into attics and wall voids |
| Brownbanded cockroach | About 5/8 inch, two light bands across the back | Indoor breeder that hides higher up, in furniture and electronics, not just the kitchen |
Clemson Extension describes the German cockroach female carrying her egg case, which holds 30 to 40 eggs, until it is nearly ready to hatch, and producing up to seven cases. That is why a few roaches turn into a lot in a matter of weeks. If you have the big ones instead, see why roaches come inside in summer, which covers the outdoor species.
Step 2: Find Where They're Living
Before you treat, find the hot spots. Purdue Extension's guide to cockroach control in multi-family housing recommends at least six sticky traps, placed:
- in the cabinets above and under the kitchen sink,
- beside the stove and the refrigerator,
- in the utility or laundry area,
- in the bathroom, along a wall or in a corner.
Rutgers researchers who trapped every unit in a 188-apartment high-rise found that traps by the stove and refrigerator caught significantly more cockroaches than traps under the sink or in the bathroom. Start there. The traps tell you where to put bait, and checking them again later tells you whether the treatment is working.
One more reason to trap: in a Rutgers study of 388 apartments in seven buildings, 36% of residents whose apartments had cockroaches didn't know they had them. Roaches stay hidden until there are a lot of them.
Step 3: Use Gel Bait, Not Sprays or Bug Bombs
This is the step most people get wrong, and the research on it is unusually strong.
| What was tested | Finding |
|---|---|
| Bug bombs (total-release foggers) in apartments, NC State, 2019 | German cockroaches from the apartments were about 202 times more resistant to cypermethrin, a common fogger ingredient, than a lab strain. More than 96% carried a gene mutation for pyrethroid resistance. The foggers killed lab roaches but not the apartment roaches |
| Bait active ingredient in the same roaches | Resistance to fipronil, a bait insecticide, was much lower: about 14 times. Bait treatments sharply reduced populations |
| Spray mixtures, Purdue, 2019 | A spray mixing two insecticides was "universally ineffective and highly repellent." Single products worked when resistance to them was low, and cross-resistance between products was a significant problem |
| Sugar in baits, NC State, 2013 | Some German cockroach populations have evolved to taste glucose, a common bait sweetener, as bitter, and avoid baits that contain it |
Sprays and foggers fail in apartments for two reasons. Most apartment roaches are already resistant to the pyrethroids in store-bought sprays, and repellent sprays drive roaches deeper into walls and into neighbors' units. Researchers studying apartment buildings have noted that movement between units can be encouraged by pyrethrin sprays.
How to bait correctly:
- Use small spots in many places. Purdue recommends a pea-size dot of gel per spot, or peanut-size where there are lots of roaches. Put it in cracks and corners near where the traps caught the most: the hinge side of cabinet doors, behind and beside the stove and refrigerator, under the sink near pipes, and the corners of drawers.
- Don't spray near the bait. Sprays and cleaners on or near the bait make roaches avoid it.
- Check after 1 to 2 weeks and reapply where bait is gone, as Purdue advises. Eaten bait is a good sign.
- If they ignore the bait, switch brands. Choose one with a different active ingredient and a different bait base. Glucose-averse roaches may refuse some formulas entirely.
- Add an insect growth regulator (IGR) if you can. IGRs stop young roaches from becoming breeding adults, which helps against the next generation.
Owner reports line up with the research. In the Reddit threads Google surfaces on apartment roaches (Reddit blocks automated reading, so we worked from Google's excerpts), about six of nine first-hand accounts credited gel bait with ending the problem, including in "an old rundown tenement building" and an apartment whose neighbors had a heavy infestation. The two that said bait wasn't working both involved units with lots of gaps or clutter, where the most common advice was to seal every crack.
Step 4: Seal the Roach Highways Between Units
German cockroaches move between apartments through the building itself. Researchers in apartment buildings have found plumbing connections to be the main corridors, and in the Rutgers high-rise study, infestations in neighboring units were linked to each other until the building-wide program broke that pattern.
- Pipe openings: fill gaps around pipes under the kitchen sink, the bathroom vanity, behind the toilet and behind the washer with caulk, foam or copper mesh.
- Outlets and switch plates on shared walls: add foam gaskets behind the cover plates.
- Baseboards and cabinet backs: caulk gaps along shared walls.
- Front door: add a door sweep if there is a gap to the hallway.
- Cardboard: don't store it. Unpack deliveries and moving boxes outside or in the hallway and recycle the boxes.
Step 5: Take Away Food and Water
Cleaning won't eliminate an infestation on its own, but it makes bait work better because the roaches have less else to eat. The Rutgers study of 388 apartments found that apartments with poor kitchen and bathroom sanitation had 2.7 times the odds of having cockroaches.
- Don't leave dishes in the sink overnight. Wipe the counters and stovetop before bed.
- Store dry food and pet food in hard containers with tight lids.
- Take the trash out nightly, and keep a lid on the can.
- Fix drips and leaks. Report any under-sink or refrigerator leak to your landlord in writing.
- Clean behind and under the stove and refrigerator, where grease and crumbs build up.
And keep cleaning after the roaches are gone. Virginia Cooperative Extension points out that cockroach allergens persist even after the cockroaches are gone. That matters in apartments: a national survey found cockroach allergen in the living rooms of about 84% of high-rise apartments.
Step 6: Get Your Landlord and Building Involved
Treating one apartment in an infested building is like bailing out one compartment of a leaking boat. Purdue's guide says good control can't be achieved without cooperation among residents, management and the pest control company. In the Rutgers building-wide program, treating every infested unit cut infested apartments by about 75% after 12 months, and most of what remained were reinfestations or new arrivals.
Here is what the law says in our three states, in plain terms. This is general information, not legal advice.
| State | Landlord | Tenant |
|---|---|---|
| Virginia | Must make all repairs and do whatever is necessary to keep the premises fit and habitable (Code § 55.1-1220). Must give 48 hours' notice before applying pesticides (§ 55.1-1223) | Must keep their unit free from insects and pests and promptly notify the landlord. The tenant can be charged for the added cost of treatment caused by an unreasonable delay in reporting (§ 55.1-1227) |
| South Carolina | Must do whatever is reasonably necessary to keep the premises fit and habitable, and keep common areas safe, and reasonably clean in buildings with more than four units (Code § 27-40-440). The act also covers landlord entry for pest treatment (§ 27-40-530) | Must keep their unit reasonably clean and dispose of garbage properly (§ 27-40-510) |
| North Carolina | Must keep the premises fit and habitable (G.S. § 42-42) | Must keep their part of the premises clean and safe (G.S. § 42-43) |
Practically, in all three states:
- Report it in writing (email or the tenant portal) as soon as you see roaches, with dates and photos. In Virginia, a delay can make you responsible for added treatment costs.
- Ask for a building-wide approach: your unit, the units on each side, above and below, and the trash and laundry rooms.
- Prepare your unit and allow access on treatment day. One unit that refuses treatment can reinfest the rest.
- Keep your own bait and traps going between visits, and keep sprays away from the bait.
- If nothing happens after written notice, talk to a local legal aid office or tenant rights group about your options.
For more, see are landlords responsible for pest control and how to prepare for cockroach extermination.
How Long It Takes
With good baiting, you should see fewer roaches within one to two weeks, and the traps should show steady drops after that. Because egg cases keep hatching, plan on several weeks of follow-up. Roaches seen in daylight, in several rooms, or coming back within weeks of treatment usually mean a heavy infestation or a source next door that also needs treatment.
When to Call a Professional
- You see roaches during the day or in more than two rooms
- Traps are still catching roaches after a month of baiting
- You manage the building, or several units are involved
- Someone in the home has asthma or allergies
Our cockroach control service uses inspection and sticky-trap monitoring, gel baits in rotation, insect growth regulators and crack-and-crevice treatment, with follow-up visits until the traps come up empty. For property managers, our commercial pest control team sets up building-wide programs for apartment communities.
Key Takeaways
- Apartment roaches are almost always German cockroaches, which breed only indoors.
- Bug bombs and sprays fail: apartment roaches were about 202 times resistant to a common fogger ingredient in NC State testing.
- Gel bait works. Use small spots where traps catch the most, usually by the stove and refrigerator, and keep sprays away from it.
- Trap first. 36% of residents with roaches in a Rutgers study didn't know they had them.
- Seal pipe gaps and outlets on shared walls.
- Treat the building, not one unit. Building-wide programs cut infested apartments by about 75% in a year.
- Report it in writing right away, especially in Virginia, where tenants must notify landlords promptly.
Sources: Z. C. DeVries, R. G. Santangelo, J. Crissman, A. Suazo, M. L. Kakumanu and C. Schal, "Pervasive Resistance to Pyrethroids in German Cockroaches Related to Lack of Efficacy of Total Release Foggers", Journal of Economic Entomology 112 (2019); M. Fardisi, A. D. Gondhalekar, A. R. Ashbrook and M. E. Scharf, "Rapid evolutionary responses to insecticide resistance management interventions by the German cockroach", Scientific Reports (2019); A. Wada-Katsumata, J. Silverman and C. Schal, "Changes in taste neurons support the emergence of an adaptive behavior in cockroaches", Science (2013), via NC State University; C. Zha, C. Wang, A. Eiden, R. Cooper and D. Wang, "Spatial Distribution of German Cockroaches in a High-Rise Apartment Building During Building-Wide Integrated Pest Management", Journal of Economic Entomology (2019); C. Wang et al., "Effectiveness of Building-Wide Integrated Pest Management Programs for German Cockroach and Bed Bug in a High-Rise Apartment Building", Journal of Integrated Pest Management 10 (2019); C. Wang, E. Bischoff, A. L. Eiden, C. Zha, R. Cooper and J. M. Graber, "Residents Attitudes and Home Sanitation Predict Presence of German Cockroaches in Apartments for Low-Income Senior Residents", Journal of Economic Entomology (2019); G. W. Bennett and C. Wang, "A Practical Guide to Cockroach Control in Multi-Family Housing" (E-241), Purdue Extension, 2017; Clemson Cooperative Extension, "Cockroach (Roach) Control" (HGIC 2449); Virginia Cooperative Extension, ENTO-528NP; R. D. Cohn, S. J. Arbes Jr. et al., National Survey of Lead and Allergens in Housing, Environmental Health Perspectives (2006); Code of Virginia §§ 55.1-1220, 55.1-1223 and § 55.1-1227; South Carolina Residential Landlord and Tenant Act, §§ 27-40-440, 27-40-510, 27-40-530; North Carolina General Statutes §§ 42-42, 42-43; owner accounts from Reddit (via Google search excerpts).
Frequently Asked Questions
Gel bait placed in small spots where the roaches live, usually beside and behind the stove and refrigerator and in cabinet hinges, combined with sticky traps to find the hot spots. You should see fewer roaches within one to two weeks. Bug bombs and sprays are slower to work, if they work at all, because most apartment German cockroaches are resistant to them.
No. NC State researchers found that German cockroaches collected from apartments where foggers had failed were about 202 times more resistant to cypermethrin, a common fogger ingredient, than a lab strain. The foggers killed lab roaches but not the apartment roaches. Foggers can also push roaches into neighboring units.
Because German cockroaches move between units through plumbing and wall gaps, and arrive in cardboard boxes, grocery bags and used appliances. Clemson Extension notes cockroaches can be found anywhere, not only in unclean places. Cleaning still helps: poor sanitation raised the odds of roaches 2.7 times in a Rutgers apartment study.
Gel bait is the best option for German cockroaches. Use pea-size spots in many places, as Purdue Extension recommends, and keep sprays away from the bait so the roaches will eat it. If they ignore one bait, switch to a brand with a different active ingredient.
In Virginia, South Carolina and North Carolina, landlords must keep rental units fit and habitable, which generally includes dealing with infestations. Virginia also requires tenants to keep their units free of pests and report them promptly, and tenants can be charged for added costs caused by a delay. Report roaches to your landlord in writing right away.
Yes. Researchers in apartment buildings have found that German cockroaches move between units, mostly along plumbing connections. In a Rutgers high-rise study, infestations in neighboring units were linked until the whole building was treated. That is why building-wide treatment works better than treating one unit.
With good baiting, you should see a drop within one to two weeks, but plan on several weeks of follow-up because egg cases keep hatching. In a building-wide program studied by Rutgers, infested units fell about 75% over 12 months.
No smell will clear an existing German cockroach infestation. Essential oils and scented products don't reach roaches hiding in walls and appliances, and some repel them deeper into hiding. Bait, sealing gaps and removing food and water are what work.
Cleaning alone rarely ends an infestation, but it helps a lot. With less food around, roaches are more likely to eat the bait. Keep cleaning after the roaches are gone, too, because Virginia Cooperative Extension notes that cockroach allergens persist after the roaches are gone.
It helps. Roaches move between connected units, so if your neighbors have them too, treating only your apartment won't last. Ask your landlord or property manager to inspect and treat the units next to, above and below yours.
Photo credits: Clemson University, USDA Cooperative Extension Slide Series, CC BY 3.0 US, via Wikimedia Commons; Gary Alpert, CC BY 2.5, via Wikimedia Commons.