Quick answer
A cockroach is a flat-bodied, fast-running insect that hides in warm, damp cracks by day and comes out at night to feed on almost any food, leaving behind droppings and shed skins that can trigger allergies and asthma.
About 55 of the world’s 3,500 species live in the U.S. Only a handful invade homes, and which one you have decides how control should work.
Quick facts
The key facts about Cockroach, with sources:
- Species in the U.S.
- About 55 of roughly 3,500 worldwide 4
- Common home pests
- German, brownbanded, oriental, American and Turkestan 1
- Adult size range
- About 1/2 inch (German) to 2 inches (American) 1
- Life stages
- Egg (inside a case called an ootheca), nymph, adult 1
- Active
- Mostly at night; hide in cracks by day 1
- Allergen in U.S. homes
- Detected in about 63% of homes in a national survey 7
Key takeaways
- Cockroaches are night-active insects that need food, water and tight hiding spots, which is why kitchens and bathrooms draw them.
- Two species, German and brownbanded, live and breed indoors; the larger American, oriental and Turkestan roaches mostly move in from outside.
- Droppings and shed skins carry allergens that are linked to asthma, especially in children in crowded housing.
- Sticky traps tell you which species you have and how many, and that answer shapes the whole treatment plan.
- Baits placed in cracks work better than sprays and foggers, which can scatter roaches into new rooms.
What a cockroach is and how it grows
Cockroaches are ancient, tough insects that have been around for more than 300 million years 4. Their flat bodies let them slip into gaps behind cabinets, under sinks and inside appliances. Long legs make them fast, and long antennae help them find food in the dark.
In science terms, cockroaches belong to the order Blattodea. They grow by simple metamorphosis: a young roach, called a nymph, looks like a small adult without full wings and sheds its skin several times as it grows 1. Females lay eggs in a hard, purse-shaped case called an ootheca.
Most of the world’s species live outdoors and never bother people. The U.S. has about 55 species, and only four or five are common pests in buildings 41.
Pest professionals sort them into two groups: indoor breeders, which spend their whole lives inside, and outdoor invaders, which live in sewers, mulch and yards and then wander in.
How a cockroach infestation grows
Every species follows the same basic loop; only the speed changes.
- Egg case. A female forms an ootheca. German roaches carry it for most of a 30-day incubation, while American roaches carry theirs for about 6 days and then glue it to a sheltered surface 1.
- Hatch. Nymphs walk out of the case. A German case releases about 30 young; an American case about 12 to 16 16.
- Grow. Nymphs feed and molt several times. The German roach goes from egg to adult in 70 to 100 days; the American can take about 600 days 26.
- Gather. Roaches cluster near food and water. Chemicals in their droppings call others to the same spot, which is why you find them in groups 2.
- Repeat. Adults mate and the next egg cases form. Under good conditions, one German female and her offspring can number more than 30,000 in a year 1.
- Egg case (ootheca)Holds about 12 to 48 eggs, by species
- NymphWingless; molts several times
- AdultWinged in most species; mates and forms new cases
- Back to step 1
Cast skins and empty egg cases left at each stage are some of the clearest signs of a breeding population. Source: [1] [2]
The cockroaches most often found in U.S. buildings
| Species | Adult size | Where it lives | Young per egg case |
|---|---|---|---|
| German | About 1/2 inch | Indoors: kitchens, bathrooms; likes 70–75°F 1 | About 30 1 |
| Brownbanded | About 1/2 inch | Indoors: warm, dry spots like electronics and behind pictures 1 | Not stated in our sources; one female line can reach 600+ a year 1 |
| Oriental | About 1 1/4 inches | Cool, damp places: basements, drains, water meter boxes 1 | One female line can reach nearly 200 a year 1 |
| Turkestan | Female about 1 inch | Meter boxes, block walls, compost, sewers 1 | Females breed faster than oriental 1 |
| American | About 1 1/2 to 2 inches | Sewers, storm drains, steam tunnels, basements 15 | About 12 to 16 15 |
Worked example: reading a week of sticky traps
This is an example of how a pro or a careful owner uses traps. The trap counts are made up to show the method; the biology behind each reading is sourced.
| Trap spot | Catch (example) | What it tells you |
|---|---|---|
| Under the kitchen sink | 14 small, tan roaches with two dark stripes, plus nymphs | German roaches breeding indoors; nymphs mean a growing population 4 |
| Behind the refrigerator | 9, same species | A second hot spot near warmth and food; bait both 1 |
| Bathroom vanity | 2 | Spread beyond the kitchen; check pipe gaps between rooms 4 |
| Basement floor drain | 1 large, reddish-brown roach | An American roach wandering in from the drain; a different fix (seal and screen the drain) 5 |
| Bedroom closet | 0 | Not established here yet |
Penn State suggests at least ten trap sites for about one week 4. Counting again after treatment shows whether numbers dropped. One house can hold two species, and each needs its own plan.
Signs of cockroaches, and where the word appears
You meet the word “cockroach” on inspection reports, service agreements and pest control invoices. On your own, you meet the signs:
- Droppings. Dark specks or smears along shelves, hinges and the backs of drawers 1.
- Cast skins and egg cases. Light-brown shells and small, bean-shaped cases in corners and cabinets 1.
- Live roaches in daylight. Seeing them by day often means a heavy population or a lack of food or water 4.
- A strong, unpleasant odor. Heavy German populations give off a telltale smell from their secretions 4.
- Allergy signs. Sneezing, watery eyes, skin rashes or worse asthma at home can point to roach allergen 4.
- On a quote. Look for the species named, the number of visits, and whether baits, monitors or exclusion work are listed. Our guide to pest control contracts covers what to check.
Why knowing the species pays off
Naming the roach is the cheapest step in control and the one that saves the most money. A German roach problem is an indoor sanitation and baiting job, while an American roach problem is often a drain, sewer or crawl-space job, so treating one like the other wastes visits.
Knowing the species also limits pesticide use. UC IPM calls sticky traps the best way to detect and monitor roaches, and says they help name the species 1. Traps show where to put bait, so less product goes into the home. Our pest identifier tool walks through the visual clues.
Why cockroaches are hard to get rid of
What works in your favor
What works against you
- German roaches have been found resistant to every class of insecticide used against them since the 1950s 3.
- Some German roaches taste glucose as bitter and refuse sugary baits, a trait called glucose aversion 3. See bait aversion.
- Baits can take 7 days or longer to work 1.
- In apartments, roaches move through shared walls, so one unit treated alone can be reinfested 2.
What drives the cost of cockroach control
We do not publish prices here, because a fair cost figure needs many dated local quotes. Species moves the price most: indoor German roaches usually need a series of bait visits, while outdoor species often need exclusion work and drain or perimeter attention.
The size of the population, the number of rooms and units, and how much clutter must be worked around all add time. Multi-unit buildings cost more to treat well because neighbors must be included 3.
Follow-up visits, often about a week apart for heavy infestations, add to the total 3. See the pest control cost guide for how plans are priced.
Waiting it out does not work. An adult German female lives about 140 to 280 days, and her egg cases keep the colony going 2. Any guarantee lasts only as long as the written agreement says.
How professional cockroach control works
A sound plan follows integrated pest management: inspect, identify, fix the causes, then treat where the roaches are.
- Inspect and trap. The technician checks kitchens, bathrooms and hidden voids and sets numbered sticky traps 1.
- Name the species. Trap catches confirm German, American or another species 1.
- Fix sanitation and moisture. Seal food, empty trash nightly, fix leaks 14.
- Seal entry points. Caulk pipe gaps and add door sweeps; trim plants away from walls for outdoor species 1.
- Place baits. Many small bait spots in cracks, not a few big ones; licensed pros rotate product types over time 3.
- Follow up. Recheck traps, add bait where needed and compare counts 3.
In most states, a company applying pesticides for pay needs a state structural pest control license. Check one with our license lookup.
Keeping roaches from coming back
Once numbers drop, these habits keep them low:
- Store dry food, including pet food, in sealed containers 43.
- Do not leave dirty dishes overnight, and empty the trash into a lidded can each night 4.
- Fix dripping pipes and wipe sinks dry; American roaches can live only about a month without water 5.
- Check boxes, grocery bags and used appliances before they come inside 4.
- Keep a few sticky traps under the sink and behind the fridge, and look at them monthly.
- Vacuum with a HEPA filter to cut allergen dust 1.
- Traps checked and replaced
- No leaks under sinks
- Food and pet food sealed
- Trash lids close tight
- Pipe gaps still caulked
Health risks and when to call a professional
The biggest health problem is allergy. Roach droppings, saliva and shed skins contain proteins that trigger allergic reactions. UC IPM links cockroach allergens to childhood asthma, especially in multi-unit housing 1.
NC State says one female German roach can make up to 1,000 units of the main allergen, Bla g 1, a day 2.
Roaches also pick up germs as they move between drains, trash and food. UC IPM says German roaches are believed to carry many disease-causing organisms, and American roaches can spread the food-poisoning bacteria Salmonella and Shigella 1. Florida IFAS reports at least 22 species of disease-causing microbes found on field-caught roaches 6.
A licensed company is worth calling when you see roaches by day, find them in more than one room, live in an apartment building, or have someone at home with asthma.
Safety first with roach products
Follow every word of the product label; the label is the law. Keep baits and dusts away from children and pets. If someone swallows a pest product, call Poison Help at 1-800-222-1222, or 911 if they collapse or cannot breathe 8.
Pesticide rules for cockroach products and foggers
Every insecticide sold for roaches in the U.S. must be registered by the U.S. EPA under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). The label sets where and how it may be used, and using it any other way is illegal. See EPA-registered pesticide and our pesticide safety guide.
Total release foggers, or “bug bombs,” carry extra EPA safety guidance.
EPA says their propellants are flammable, they should be kept at least six feet from flames and pilot lights, never used in small spaces such as cabinets, and everyone, including pets, must leave for the time on the label, usually two to four hours 8.
Anyone paid to treat roaches must hold a state pesticide license. Rules on categories, training and record-keeping differ by state; our licensing guide explains the basics.
Cockroach vs other kitchen and bathroom pests
| Pest | Size and look | Where it shows up | Main clue |
|---|---|---|---|
| Cockroach | 1/2 to 2 inches, flat, brown, long antennae 1 | Under sinks, behind appliances, drains | Droppings, egg cases, night movement 1 |
| Silverfish | Smaller, silvery, carrot-shaped; no wings | Damp bathrooms, basements, paper storage | Seen near paper and damp areas |
| Bed bug | 5–7 mm, oval, reddish-brown | Mattress seams and furniture | Shed skins and spots on bedding |
| Fruit fly | Tiny flying insect | Around ripe fruit and drains | Small flies hovering over produce |
Not sure which one you have? Start with pest identification before anyone treats.
Common cockroach myths
- Myth A bug bomb will wipe them out.
- Reality Penn State says foggers inside a home have little value against German roaches and can scatter them, making control slower 4.
- Myth Roaches only live in dirty homes.
- Reality They ride in on boxes and bags and travel through walls in apartments 42.
- Myth More bait is better.
- Reality NC State advises many small, pea-sized bait spots rather than a few large ones 3.
- Myth Any sweet bait will work.
- Reality Some German roaches reject glucose-based baits; pros switch to a different bait base 3.
- Myth A big roach in the basement means the kitchen is infested.
- Reality A lone large roach from a drain is often an American roach wandering in from outside, a different problem from an indoor German infestation 5.
How region and housing change the picture
A national survey of 831 homes (the National Survey of Lead and Allergens in Housing, 1998–1999) found roach allergen above the 8.0 U/g asthma-risk level on kitchen floors in 12.9% of Southern homes and 11.5% of Western homes, versus 4.3% in the Northeast and 6.6% in the Midwest.
High-rise apartments had the highest rates of all 7. Species also shift by place: UC IPM reports the Turkestan cockroach displacing the oriental cockroach in Southern California and the Central Valley 1. Our calendar shows when roaches peak where you live.
What to do if you see a cockroach
A single large roach near a drain in summer usually calls for sealing and screening the drain, then watching.
Small roaches in the kitchen, any nymphs, or roaches in daylight mean it is time to set traps for a week and call a licensed company.
If anyone at home has asthma, act sooner, because removing roaches lowers allergen levels 2.
When you compare companies, ask how they confirm the species, whether they use traps to measure results, and how many follow-up visits are included. Our cockroach control service page explains what a full job includes.
Quick decision guide
For one big roach from a drain, seal and monitor. For small roaches or nymphs indoors, trap, then call a pro. In an apartment building, ask management to treat nearby units too.
Questions about Cockroach
What attracts cockroaches to a house?
Food, water and tight, warm hiding spots attract cockroaches. Crumbs, pet food, open trash and dirty dishes give them food. Leaky pipes and damp sinks give them water.
Gaps behind cabinets and appliances give them shelter. Outdoor species are also drawn in by mulch, ivy and damp areas near the foundation, which UC IPM advises trimming back from walls.
Are cockroaches dangerous to people?
Cockroaches are mainly a health risk through allergens and germs. Their droppings and shed skins carry proteins linked to asthma, especially in children.
UC IPM says German roaches are believed to carry many disease-causing organisms, and American roaches can spread Salmonella and Shigella.
They do not bite people in normal home settings, but they can contaminate food and surfaces.
Can cockroaches fly?
Some cockroaches can fly, but most home species rarely do. German roaches have wings but do not fly.
Penn State says American roaches rarely fly in northern areas, though they have been seen flying between buildings in warm months.
Flying is not a useful clue to the species; size, color and markings on the plate behind the head tell you more.
Does seeing one cockroach mean an infestation?
One cockroach does not always mean an infestation, but it is worth checking. A single large roach near a drain may be an outdoor species that wandered in.
A small German roach indoors is more concerning, because they breed fast inside. Set sticky traps in the kitchen and bathroom for a week to find out whether more are present.
How fast do German cockroaches multiply?
German cockroaches multiply very fast. Each egg case holds about 30 to 48 eggs, and a female makes 4 to 8 cases in her life, per Penn State. UC IPM says one female and her offspring can produce more than 30,000 roaches in a year under ideal conditions. That speed is why early action matters.
Do bug bombs work on cockroaches?
Bug bombs usually do not work well on cockroaches. Penn State says foggers inside a structure have little value against German roaches and can scatter them into new areas. The EPA also warns that fogger propellants are flammable. Baits placed in cracks and hiding spots, along with sanitation, work better.
What is the difference between a palmetto bug and a cockroach?
A palmetto bug is a cockroach. The name is a regional nickname, used mostly in the South, for large outdoor roaches such as the American or smokybrown cockroach.
“Water bug” is another common nickname. The name changes, but the biology does not, and these large species usually come in from outside rather than breeding in kitchens.
How long can cockroaches live without food?
Large cockroaches can live for months without food but not long without water. Penn State says adult American roaches can survive 2 to 3 months without food but only about one month without water. This is why fixing leaks and drying sinks is one of the most useful steps against them.
Why do cockroaches come back after treatment?
Cockroaches often come back because some survived, eggs hatched later, or new ones moved in. Egg cases protect developing young, and many German roach populations resist common insecticides. In apartments, roaches move from untreated units next door. Follow-up visits and ongoing trap checks catch a rebound early.
Should I call a professional for cockroaches?
Call a licensed professional if you see roaches in daylight, find them in several rooms, live in a multi-unit building, or have someone with asthma at home. NC State Extension advises hiring a pest management company for German roaches, since pros have several bait types and are trained to read the signs.
Sources
- UC Statewide IPM Program, Pest Notes: Cockroaches (Publication 7467), retrieved .
- NC State Extension, Biology and Behavior of the German Cockroach, retrieved .
- NC State Extension, German Cockroach Surveillance and Management (2025), retrieved .
- Penn State Extension, German Cockroaches, retrieved .
- Penn State Extension, American Cockroaches, retrieved .
- University of Florida IFAS, American Cockroach, Periplaneta americana (EENY141/IN298), retrieved .
- Cohn et al., National Prevalence and Exposure Risk for Cockroach Allergen in U.S. Households, Environmental Health Perspectives (NIEHS/HUD survey), retrieved .
- U.S. EPA, Safety Precautions for Total Release Foggers, retrieved .
Expert review
Written by the HyrePest Research team. Not yet reviewed by an outside expert. We say so rather than imply a review that has not happened; see our editorial policy.
How the numbers were checked: Species, sizes, egg-case counts and health facts follow UC IPM Pest Notes 7467.
German roach biology and allergen output are from NC State Extension; American roach figures are from Penn State and UF/IFAS, attributed where they differ.
Allergen prevalence is from the NIEHS/HUD national housing survey. Fogger rules are from the EPA.
Suggest a correction. We fix errors and say what changed.