No water: about 2 weeks (Oriental; German) to a month (American) (Penn State; Willis & Lewis 1957). No food, with water: about a month for German and Oriental adults, 2–3 months for American (Virginia Tech; Penn State). Neither: 14–20 days for German adults, about 28 (males) to 42 days (females) for American (Willis & Lewis 1957; Ashby 2017).
How long can a cockroach live without water?
Not long. How long can a cockroach live without water? For most adults, about two weeks to a month, even with food on hand. Oriental cockroaches "die within two weeks" without water (Penn State); American adults last "only about a month without water" (Penn State); and in the classic Willis & Lewis (1957) tests at 27 °C, newly emerged German females given dry dog biscuit but no water lived just 14.7 days on average (quoted by Ebeling). The National Pest Management Association's own figure is one week without water.
Water is the hard limit because cockroaches lose it all the time, through their cuticle and their breathing holes, and dry air speeds that up. In a University of Florida study, first-stage American nymphs kept without food or water in dry wood didn't survive a single day, while the same nymphs at very high humidity lasted up to 25 days (Ashby 2017).
- How long can a roach live without water if it's a German roach: about 15 days with food, 14–20 days with nothing.
- How long can a cockroach survive without water if it's an American cockroach: about 30–40 days with food (females), 28–30 days for males.
- How long can roaches go without water if they're Oriental: within two weeks.
So how long do roaches live without water? Weeks, not months — which is why every extension guide puts fixing leaks near the top of the list.
How long can a cockroach live without food?
Much longer — if there's water. How long can a cockroach live without food? About a month for German and Oriental adults (Virginia Tech; Penn State) and two to three months for American adults (Penn State). Willis & Lewis measured 35.1 days for newly emerged German females with water but no food, and 89.6 days for American females — about three months (Ebeling; Ashby 2017).
Put another way, how long can a roach live without food depends mostly on its size: big roaches carry bigger reserves. How long can a cockroach survive without food at 27 °C if it's a German roach? About a month. How long can roaches go without food if they're American? Up to three months. And how long do roaches live without food compared with a normal life? In the same tests, well-fed German females lived 82 days and American females 190 days — so the cockroach lifespan without food is roughly half the fed lifespan when water is available (Willis & Lewis 1957).
Those are averages. Searches such as how long can a roach survive without food, how long can cockroaches survive without food or how long do cockroaches live without food usually quote "a month", which matches the German and Oriental figures; the timer above gives the range for each species and sex. For their normal lifespan with food, see the cockroach lifespan calculator.
What do cockroaches eat when there is no food?
Almost anything. American cockroaches have been recorded eating bread, fruit, paper, leather and hair (Nigam 1933, quoted by Ashby 2017), and the starved American cockroaches in Ashby's study chewed the pine wood they were kept in — but eating wood didn't keep them alive any longer. Ebeling describes German cockroaches living for months in the insulation of refrigerators and stoves, "feeding only on cast skins and dead insects", and notes that a German female will eat her young nymphs if she has no water (Ross 1929). Crumbs, grease, glue, soap and pet food all count as food to a roach.
How long can cockroaches live without food and water?
About two to six weeks, depending on species and sex. How long can a cockroach live without food and water? Willis & Lewis (1957) found newly emerged German females lived 20.1 days and American females 41.7 days with neither, at 36–40% humidity (Ebeling); American males lasted about 28 days (Ashby 2017). Virginia Tech's summary for German adults is two weeks. The full table by species and sex:
| Species | Sex | No food (has water) | No water (has food) | No food and no water |
|---|---|---|---|---|
| German cockroach | females | 30–35 days | 15 days | 14–20 days |
| German cockroach | males | 30 days | 14 days | 14 days |
| American cockroach | females | 60–90 days | 30–40 days | 42 days |
| American cockroach | males | 60–90 days | 28–30 days | 28 days |
| Oriental cockroach | adults | 30 days | 14 days | 14 days |
| Brown-banded cockroach | — | Not measured (closest: German) | Not measured (closest: German) | Not measured (closest: German) |
| Smokybrown cockroach | — | Not measured (closest: American) | Not measured (closest: American) | Not measured (closest: American) |
Sources: Willis & Lewis 1957 (via Ebeling and Ashby 2017) for German females and American adults; Virginia Tech for German adults; Penn State and NPMA for Oriental adults and American ranges. Where food-without-water wasn't measured, it is taken as equal to no food and no water, because Willis & Lewis found the two lasted about as long. Brown-banded and smokybrown cockroaches weren't in any study we could verify.
So how long can a cockroach live without food or water — whichever one is missing — has a clear answer: losing water is worse. How long can a roach live without food and water? Two to six weeks. How long can a roach live without food or water on its own? Water: two to six weeks; food: one to three months. How long can cockroaches live without food and water or how long can cockroaches live without food or water in a cool, humid basement may be longer, and in a hot, dry room shorter.
Why water matters more than food
Do cockroaches need water? More than they need food. Three findings explain why:
- Dry food doesn't help. German and American cockroaches given dry food but no water lived no longer — even slightly shorter — than those given nothing at all: 14.7 vs 20.1 days for German females and 40.1 vs 41.7 for American females (Willis & Lewis 1957, via Ebeling). Digesting dry food costs water.
- Water alone keeps them going. With water but no food, the same insects lived about 1.7 (German) and 2.1 (American) times longer than with nothing.
- Humidity is a lifeline. Cockroaches survived longest at the highest humidity in Ashby's study, and in Dambach & Goehlen (1998) starved first-stage German nymphs lived up to 9 days at 2% humidity but more than 30 days at 75.5% (quoted by Ashby 2017). Laboratory work on cockroach breathing shows they keep their spiracles shut longer in dry air to save water (Schimpf, Matthews & White 2009).
Where cockroaches find water indoors
Even a tidy home offers water. The sources extension guides tell you to check:
- Leaks and drips under sinks, behind dishwashers and washing machines, and in basements and crawl spaces (Penn State; Texas A&M).
- Pet bowls left full overnight (Texas A&M; University of Kentucky).
- Wet mops, sponges and cloths left on the floor or by the sink (Texas A&M).
- Dishes soaking overnight and spills that haven't been wiped up (Penn State; CDC).
- Sinks, tubs and drains that stay wet — the reason the planner above asks you to dry them at night.
That's why Oriental cockroaches gather "in one great mass around leaks in the basement" (Penn State), and why American and Oriental cockroaches favour drains and sewers (Texas A&M). It's also why extension services list water first: "Remove as many water and food sources as you can" (CDC).
Can you starve out cockroaches?
Can you starve cockroaches out of a home? Not on its own. Starvation works only if every source is gone, and cockroaches find water in sink traps, condensation, pet bowls and leaks, and food in crumbs, grease, paper and dead insects. What sanitation does do is stress the population: "When food or water is scarce, cockroaches must search farther each night to survive. Good sanitation puts stress on cockroach populations and increases the effectiveness of baits" (Texas A&M). Baits, in turn, "are most effective when few food alternatives are available".
Baby cockroaches without food or water
Nymphs are the first to go, and humidity decides how fast. Starved, water-deprived first-stage German nymphs lived up to 9 days at 2% humidity, 11 days at 22.5%, 18 days at 50.5% and more than 30 days at 75.5% (Dambach & Goehlen 1998, quoted by Ashby 2017). In Ashby's own University of Florida study of American cockroaches kept without food or water in pine blocks, no first-stage nymph survived a full day in the driest blocks; the longest-lived first instar lasted 25 days, the longest adult 53 days — and the longest third- to fourth-stage nymph 104 days. Half-grown nymphs, in other words, outlasted both the hatchlings and the adults. Drying out a room hits the youngest roaches hardest, but the mid-sized ones can hang on for months.
Will cockroaches leave if there is no food?
Will cockroaches leave if there is no food? They don't pack up and go, but hungry roaches range farther, and in apartments they travel between units through shared walls and ceilings (University of Kentucky). Seeing roaches in daylight is often a sign of a large population or of stress such as food or water running short (Penn State). Clearing food and water makes them easier to find, trap and bait — it rarely makes them disappear without other control. For a realistic, week-by-week timeline that combines sanitation, monitoring and baits, see how long it takes to get rid of cockroaches.
Cockroaches in an empty house
Cockroaches in an empty house can hang on for weeks if there's any water: a dripping tap, a toilet bowl or a damp basement. Without water, the table gives the limit — about two to six weeks for adults. Eggs already laid can hatch later, and Oriental egg cases resisted drying so well that eggs kept at 0% humidity still hatched after about 46 days (Roth & Willis 1955, quoted by Ebeling). Before leaving a property empty, fix leaks, dry out sinks and drains, and remove every scrap of food. The same logic applies to bed bugs in an empty home, which have very different numbers — see how long bed bugs live without a host.
For a heavy or persistent infestation, a licensed pest professional is the reliable route. Cockroach droppings, saliva and shed skins contain allergens that can trigger asthma (CDC; Penn State), and the CDC advises avoiding sprays and foggers, which can trigger attacks too.
How this survival timer works
The timer and the planner use the shared cockroach data model on this site, so these survival times are the same on every cockroach page.
- Survival range: for the species, sex and situation you choose, the low and high published adult figures — for example Virginia Tech's "two weeks" and Willis & Lewis's 20.1-day average for German adults with nothing. "Not sure" combines both sexes.
- Status: "Likely still alive" before the low figure, "Many dying" between the low and high figures, and "Most likely dead" after the high figure. The date is today plus the days left to the high figure.
- Not measured: brown-banded cockroaches use German figures (a similar-sized indoor relative) and smokybrown use American figures (same genus); the result says so.
- Planner: a checklist of the water, food and shelter sources the CDC, Penn State, Texas A&M and the University of Kentucky recommend removing, with the survival numbers that show why water comes first.
Willis & Lewis kept their roaches at 27 °C and 36–40% humidity. Cooler, damper places extend survival; hot, dry rooms shorten it.
Frequently asked questions
How long can a cockroach live without water?
About two weeks to a month for adults. Oriental roaches die within two weeks (Penn State), American adults last about a month (Penn State), and German females with dry food but no water averaged 14.7 days (Willis & Lewis 1957).
How long can a cockroach live without food?
About a month for German and Oriental adults if they have water (Virginia Tech; Penn State) and two to three months for American adults (Penn State).
How long can a cockroach live without food and water?
About 14–20 days for German adults, 28 days for American males and about 42 days for American females (Willis & Lewis 1957; Virginia Tech).
How long can roaches go without water if they have food?
Barely longer than with nothing: dry food without water gave German females 14.7 days vs 20.1 with nothing (Willis & Lewis 1957).
Do cockroaches need water more than food?
Yes. With water but no food they lived 1.7–2.1 times longer than with nothing; with food but no water, no longer at all (Willis & Lewis 1957).
Can you starve cockroaches?
Not reliably on your own. They find water and scraps almost anywhere. Sanitation stresses them and makes baits work better (Texas A&M); a licensed professional is best for heavy infestations.
Will cockroaches leave if there is no food?
They search farther each night (Texas A&M) and in apartments can move between units (University of Kentucky), but they rarely just leave.
What do cockroaches eat when there is no food?
Paper, leather, hair, cast skins, dead insects, glue and grease. German females may eat their own nymphs when water is short (Ross 1929, via Ebeling).
How long do cockroaches live in an empty house?
Weeks if there's any water, such as a dripping tap or toilet bowl; about 2–6 weeks for adults with no water at all.
Do baby cockroaches survive without food and water?
Not for long. Starved first-stage German nymphs lived 9–11 days in dry air and over 30 days in humid air (Dambach & Goehlen 1998); dry first-stage American nymphs died within a day (Ashby 2017).
Does humidity change how long roaches survive?
Yes. Higher humidity means slower water loss and longer survival (Ashby 2017; Dambach & Goehlen 1998).
What is the cockroach lifespan without food?
Roughly half the normal adult lifespan if water is available: 35 vs 82 days for German females and 90 vs 190 days for American females (Willis & Lewis 1957).
Why do cockroaches gather around leaks and drains?
They need water constantly. Oriental cockroaches mass around basement leaks (Penn State), and American and Oriental roaches use floor drains (Texas A&M).
These calculators give estimates from laboratory and extension figures, for education. Real cockroaches vary with strain, food, humidity and insecticide exposure. Cockroach droppings, saliva and shed skins contain allergens that can trigger asthma, especially in children (CDC; Penn State; University of Kentucky) — for health questions, talk to a doctor. For a heavy infestation, contact a licensed pest professional or your local extension service. We give no pesticide advice.