How Long Do Cockroaches Live? Lifespan by Species
A German cockroach lives about 200 days on average, while American and Oriental cockroaches develop more slowly and often live well over a year from egg to death. As adults, German females live 20 to 30 weeks, American females up to about 15 months and Oriental females 5 to 26 weeks. Without food, a classic laboratory study found adult German cockroaches lived about 35 days on water alone and American cockroaches about 90. Without water they die much sooner, which makes moisture the weak point worth targeting.
“How long do cockroaches live” has three different answers: how long one roach lives with everything it needs, how long it lasts when you take food or water away, and how long an infestation lasts. The first is set by species and temperature. The second comes from laboratory starvation studies, which are older and more specific than most web pages admit. The third is the one that matters at home, because a population can outlive every individual in it.
Cockroach lifespan by species
| Species | Egg stage | Nymph stage | Adult life | Where it lives |
|---|---|---|---|---|
| German | 14 to 35 days, carried by the female | 6 to 31 weeks, 6 or 7 moults | Females 20 to 30 weeks | Entirely indoors |
| American | 29 to 58 days | 160 to 971 days, 6 to 14 moults | Females up to about 15 months; males shorter | Outdoors and in sewers; invades |
| Oriental | About 60 days | 24 to 130 weeks, 7 to 10 moults | Females 5 to 26 weeks | Outdoors; invades |
Figures from Penn State Extension fact sheets for each species, with moult counts for the American cockroach from UF/IFAS. Ranges are wide because temperature drives development: warm kitchens push every stage toward the short end.
German cockroach
Penn State gives an egg stage of 14 to 35 days and six to seven nymphal stages over 6 to 31 weeks, with adult females living 20 to 30 weeks. Older laboratory work summarised in Urban Entomology (Ebeling, UC Riverside) found an individual German cockroach lives an average of 200 days at room temperature and may live as long as 10 months. Females form their first egg case 11 or 12 days after becoming adults. The species is short-lived but fast: Ebeling notes it lays more eggs and has more generations a year than the other common house cockroaches, so its numbers rise much more rapidly. Our German cockroach treatment guide covers what works.
American cockroach
The largest common house cockroach is also the longest-lived. Penn State says an adult female can live up to 15 months under ideal conditions, with males living somewhat less. UF/IFAS gives nymphal development of six to twelve months and says adults can live up to one year. In a study at 84°F (29°C) summarised by Ebeling, adult life ranged from 90 to 706 days for females (average 225) and 90 to 362 days for males (average 200), and total life expectancy averaged over 630 days, with one individual reaching 1,293 days.
Oriental cockroach
Oriental cockroaches develop slowly: Penn State gives 24 to 130 weeks as nymphs and an adult female life of 5 to 26 weeks. Ebeling notes development takes more than a year even indoors, up to about 2 years for some. Adults appear mostly in late spring and early summer, according to Penn State, and our data shows the same peak.
Not sure which species you have? Our cockroach identification guide compares them at the same scale, and baby cockroaches covers the nymphs.
How long can a cockroach live without food or water?
The figures quoted across the web trace back, usually without credit, to a 1957 study by Willis and Lewis in the Journal of Economic Entomology. Ebeling reports its results for newly emerged adult females kept at 81°F (27°C) and 36 to 40 per cent relative humidity:
| Condition | German female (days) | American female (days) |
|---|---|---|
| No food, no water | 20.1 | 41.7 |
| Dry food, no water | 14.7 | 40.1 |
| Water, no food | 35.1 | 89.6 |
| Food and water | 82 | 190 |
Three things stand out. Water matters more than food: with water and no food, both species lived well over twice as long as with neither. Dry food without water was slightly worse than nothing at all, which Ebeling calls interesting without explaining. And the American cockroach outlasted the German in every condition by roughly two to one.
Humidity changes the answer
The 1957 study was run in fairly dry air. A 2015 study in Biotemas (Duarte and colleagues, Federal University of Pelotas) repeated the test on American cockroaches at 77°F (25°C) and 70 per cent humidity, closer to a sewer or damp basement. Survival was longer. The median lethal time with no food and no water was 55.1 days for females and 48.5 for males; with no water but with food, 93.1 and 60.7 days; with no food but with water, 99.6 and 69.0 days. Females outlived males whenever only one resource was removed. The authors put the difference from the 1957 results down to humidity.
So the honest answer for an American cockroach is “about one to three months without food, depending on humidity and sex”, and for a German cockroach “about a month on water alone, two to three weeks with nothing”. Anyone giving a single number is simplifying.
How long can a cockroach live without its head?
Weeks, according to Joseph Kunkel, a physiologist at the University of Massachusetts Amherst who studied cockroach development, quoted in Scientific American in 2007. He explained that the neck often seals by clotting so there is no uncontrolled bleeding, that cockroaches breathe through spiracles in each body segment rather than through the head, and that the brain does not control that breathing. Because insects are cold-blooded and need little food, he said, one can survive for weeks on a single meal, unless it is infected by mould, bacteria or a virus.
The popular version, that a headless roach lives “about a week” and then dies of thirst, is not what that source says. Kunkel said weeks, and named infection as the end. We found no controlled study giving a precise figure, so treat it as a striking fact rather than a measured one.
How many eggs can a cockroach lay in a day?
Usually none. Cockroaches lay eggs in a case, one case at a time, not daily. Penn State gives up to 48 eggs per German cockroach case (usually 30 to 48) and four to eight cases in a lifetime; an American cockroach case averages 14 to 16 eggs, usually one case a week, and 15 to 90 cases in a lifetime. Our guide to cockroach eggs covers hatching times and what the cases look like.
Our data: when each species is seen
The Pest Control Brief analysis of iNaturalist research-grade records, pulled October 2026, shows three distinct patterns once observer effort is removed. Oriental cockroaches peak in July (index 174), matching Penn State’s late spring and early summer adult peak. American cockroaches are above average from September to December, peaking in November (155). German cockroaches peak in winter (184 in November, 176 in December, 171 in January).
The German cockroach’s winter peak does not mean it breeds more in winter. It lives indoors year-round; its share of records rises because there is little else outdoors for people to photograph. The index is a cockroach’s share of all US research-grade observations that month, scaled so the yearly mean is 100. These are sightings, not infestation rates.
How long will a cockroach stay in your house?
As long as it finds food, water and shelter, and for German cockroaches that means indefinitely. UC IPM notes that German and brownbanded cockroaches live and breed entirely indoors, while American, Oriental and Turkestan cockroaches live outdoors and invade temporarily. An individual German cockroach lives months, but its population continues for as long as conditions allow. A single American or Oriental roach wandering in from outside is often a one-off; several, or nymphs, suggest a breeding source nearby. UC IPM notes that a few species fly short distances or glide on warm nights; see can roaches fly for which ones.
Their weak point, and what to do about it
Water is the weak point. In a Purdue University laboratory study of German cockroach populations (Bertholf, 1983), removing water, alone or with other factors, affected adult mortality within a week, while removing food had a slower, intermediate effect and removing harbourage had no significant effect on mortality. Willis and Lewis’s figures point the same way.
| Step | Why it works | DIY or professional |
|---|---|---|
| Fix leaks, dry sinks and drains overnight | Water deprivation cuts survival fastest | DIY |
| Store food sealed, clean spills, lidded bins | Removes food; makes baits more attractive | DIY |
| Gel or granular baits in cracks where roaches hide | UC IPM: baits give better control than sprays | DIY for light activity; follow the label |
| Vacuum cracks, shed skins and egg cases | Removes roaches and cases directly | DIY |
| Established German cockroach infestation | Fast breeding; UC IPM notes baits do not control all cockroaches equally | Licensed professional usually needed |
UC IPM advises avoiding foggers, bombs and aerosol sprays, which can be hazardous and may scatter cockroaches to other areas without killing them. Pesticides alone will not solve the problem without sanitation and exclusion. Our comparison of cockroach bait and spray sets out the evidence, and cockroach exterminator costs covers what professional treatment usually involves.
Frequently asked questions
What is the best way to kill cockroaches?
Baits combined with sanitation. UC IPM says baits provide better control than sprays, that pesticides alone will not solve cockroach problems, and that foggers and bombs can scatter roaches without killing them. Place gel or granular bait where roaches hide, remove competing food and water, and vacuum egg cases. For an established German cockroach infestation, a licensed professional is usually the quicker route.
Why should you never kill a roach?
There is no good reason not to. Claims that killing one releases eggs or attracts others are not supported by the extension sources we read. Two cautions make sense: crushing a roach smears allergens and bacteria, so wipe the surface clean; and a German female carries her egg case for up to a month, so dispose of the case as well. Vacuuming avoids both problems.
What is a cockroaches’ biggest weakness?
Lack of water. In the 1957 Willis and Lewis study, German cockroach females lived 35.1 days with water but no food, and only 14.7 days with dry food and no water. A Purdue study found water removal raised adult mortality within a week. Fixing leaks and drying sinks overnight therefore does more than most sprays, and it makes baits more effective.
How long do cockroaches live without water?
Much less time than without food. In the 1957 Willis and Lewis study, in fairly dry air, German cockroach females given dry food but no water lived 14.7 days on average and American females 40.1 days. In humid air at 70 per cent, a 2015 study found American cockroaches with food but no water had median survival of 60.7 days for males and 93.1 for females.
Can a cockroach live without its head?
Yes, for weeks, according to physiologist Joseph Kunkel quoted in Scientific American. The neck clots so it does not bleed out, and it breathes through spiracles along its body, which the brain does not control. Kunkel said a headless roach survives until infection by mould, bacteria or a virus kills it. No controlled study gives a precise number of days.
Sources
- Penn State Extension, German Cockroaches, American Cockroaches and Oriental Cockroaches fact sheets (Jacobs), revised 2013.
- University of Florida IFAS, Featured Creatures EENY-141, American Cockroach, Periplaneta americana, revised 2024.
- Ebeling, Urban Entomology, chapter 6, Pests On or Near Food, University of California Riverside Department of Entomology, reporting Willis and Lewis (1957), Gould and Deay (1940) and Griffiths and Tauber (1942).
- Willis and Lewis, The longevity of starved cockroaches, Journal of Economic Entomology 50(4), 1957.
- Duarte, Felchicher, Ribeiro and Cárcamo, Survival and weight change among adult individuals of Periplaneta americana subject to various stress conditions, Biotemas 28(2), 2015.
- Bertholf, The influence of sanitation on German cockroach populations, PhD dissertation, Purdue University, 1983.
- Choi, Fact or Fiction?: A Cockroach Can Live without Its Head, Scientific American, 2007 (interview with Joseph Kunkel, University of Massachusetts Amherst).
- University of California Statewide IPM Program, Pest Notes: Cockroaches, Publication 7467 (Sutherland, Choe and Rust).
- The Pest Control Brief analysis of iNaturalist research-grade records, pulled October 2026.
