Without food (with water): 63–70 hours at 21 °C and 46–51 hours at 25 °C on average (Da Lage et al. 1989). Without food or water: 21–27 hours at 21 °C. After the source is removed: about 4.6 days at room temperature for the last adults to die — or about 17.6 days if eggs may still be developing in a spot you haven't checked.
How long can fruit flies live without food?
Only a few days. The best study of this kept adult fruit flies with water but no food at nine temperatures from 5 to 31 °C and timed how long they survived (Da Lage et al. 1989). At a room temperature of 21 °C (70 °F), average survival was about 63–70 hours; at 25 °C (77 °F), about 46–51 hours — roughly two days. That's the answer to how long do fruit flies live without food: two to three days on average in a normal room.
Cold stretches it. At 15 °C (59 °F) the flies averaged 100–114 hours, because a cold fly burns its fat reserves more slowly. Males with water outlived females at every temperature, and the coefficient of variation was 26–29%, which means some flies lasted well beyond the average. A 2025 lab study at 25 °C gives a similar picture: control flies with only water survived 74 hours on average for females and 47 hours for males (Chen et al. 2025). Different fly strains and how well fed the flies were beforehand explain the differences.
Compare that with a fly that has food: adults in a home normally live for weeks (see the fruit fly lifespan calculator). So fruit flies' lifespan without food is cut from weeks to days.
And how long do fruit flies live without fruit? Fruit is only their favourite food. Juice spills, wine and beer dregs, sweet residue in the recycling and the film in a drain all feed adults and larvae, so taking away the fruit bowl starts the clock only if nothing else sweet or fermenting is left. Once it truly is gone, how long can fruit flies survive without food in a normal room? The same two to three days as above.
Fruit flies lifespan without food and water
Can fruit flies survive without food and water? Not for long. In bone-dry air with no food, the same 1989 study found survival fell to well under a day at room temperature. In dry air, females outlived males — the opposite of the result with water — probably because males are smaller and lose water faster.
| Temperature | No food, with water: males | No food, with water: females | No food or water: males | No food or water: females |
|---|---|---|---|---|
| 15 °C (59 °F) | 114 h | 100 h | 44 h | 54 h |
| 18 °C (64.4 °F) | 89 h | 79 h | 30 h | 38 h |
| 21 °C (69.8 °F) | 70 h | 63 h | 21 h | 27 h |
| 25 °C (77 °F) | 51 h | 46 h | 13 h | 17 h |
| 28 °C (82.4 °F) | 40 h | 36 h | 9 h | 12 h |
| 31 °C (87.8 °F) | 31 h | 29 h | 6 h | 8 h |
Figures are averages from Da Lage et al. (1989); individual flies vary by roughly a quarter either way. How long do fruit flies live without water? In a real kitchen, flies rarely run out of water completely: sinks, condensation, damp cloths and plant saucers are everywhere. That's why the calculator uses the "with water" survival time and treats total dryness as the rare best case.
How long does it take fruit flies to die once the source is gone?
How long does it take fruit flies to die after you throw out the rotten fruit? There are two clocks running:
- The adults you can see. With no food, they die off over a few days. At 21 °C the calculator puts the last stragglers at about 4.6 days after the source goes; at 25 °C about 3.3 days.
- Flies still developing somewhere else. If eggs, larvae or pupae are hiding in a second spot, new adults keep appearing for up to 13 days at 21 °C — the time from egg to adult — plus their own survival time.
So how long for fruit flies to die in total — and how long does it take to get rid of fruit flies? If you're sure the only source is gone, about 4–5 days at room temperature. If you're not sure, allow about 17.6 days at 21 °C. The calculator gives you the date for your situation, with a status bar: "Should be gone by …", "Check the other spots" or "Still breeding — find the source".
One caveat: those survival times assume no food at all. A drop of spilled juice, a sticky bottle in the recycling or a sweet residue in the sink can keep adults going for longer.
How long do fruit flies last in a house?
How long do fruit flies last in a home? As long as they have somewhere to breed. Iowa State University calls fruit flies "usually a temporary annoyance" that often disappear on their own. That's true when the source is a single piece of fruit that gets eaten or thrown away. But will fruit flies go away on their own if they're breeding in a drain or a forgotten onion? No — one rotting potato or onion can breed thousands of fruit flies (University of Kentucky). So do fruit flies go away on their own? Only once every breeding spot is gone; until then, new adults replace the ones that die.
Why do I still have fruit flies?
Why do I still have fruit flies after throwing out the fruit? Because the fruit wasn't the only source. New adults appear about 13 days after eggs are laid at 21 °C, so flies seen a week or more after the clean-up almost certainly hatched somewhere else. The usual suspects are drains, the garbage disposal, the recycling bin, mops and cleaning rags (University of Kentucky). How long does a fruit fly infestation last when the real source is found? A few days more, while the last adults die.
For how fast a missed source fills the house, see the fruit fly life cycle calculator.
Hidden fruit fly breeding spots
Where are fruit flies breeding in my house? Anywhere there is fermenting organic matter that stays wet or moist (Iowa State University). Work through this checklist — the calculator uses the same list and warns you about any spot you haven't ticked:
| Place | What to look for |
|---|---|
| Fruit bowl & overripe produce | Ripe or fermenting fruit and vegetables, including a single rotting potato or onion (UKy ENTFACT-621). |
| Trash & recycling bins | Trash containers, empty bottles and cans, and an uncleaned recycling bin (UKy ENTFACT-621). |
| Drains & garbage disposal | Slime above the water line in slow or seldom-used drains, and garbage disposals (Iowa State; UKy). |
| Mop, sponge & cleaning rags | Damp mops and cleaning rags (UKy ENTFACT-621). |
| Compost caddy | Any fermenting organic matter that stays wet (Iowa State Extension). |
| Houseplants | Moist potting soil breeds fungus gnats rather than fruit flies (UC IPM) — worth ruling out. |
Fruit flies in the drain
Fruit flies in the drain breed in the layer of slime above the water line in slow or seldom-used sink, bath, shower and floor drains (Iowa State). To check, tape a clear plastic bag or film over the drain overnight; if adults gather underneath by morning, that drain is a source (University of Kentucky; Iowa State). Scrubbing the drain with a stiff brush may be all that's needed.
Does temperature change how fast they die off?
Yes. A warm fly burns through its reserves faster, so the same hungry adults last about 36–40 hours at 28 °C (82 °F) but noticeably longer in a cool room (Da Lage et al. 1989). That's why the calculator asks for your room temperature and works out the date from it.
Do fruit flies die in winter or in the fridge? →
How to make fruit flies go away faster
How to get rid of fruit flies fast, without pesticides — extension services agree that finding the source matters most, and that insecticides alone won't solve it (University of Kentucky):
- Eat, throw out or refrigerate ripe fruit and vegetables, and cut away damaged parts (University of Kentucky).
- Make a cider-vinegar trap: a jar baited with cider vinegar and a paper funnel in the top catches remaining adults (University of Kentucky); vinegar with a drop of dish soap also works (ENTFACT-657).
- Test and clean drains with the overnight plastic-bag test, a stiff brush and, if needed, slowly poured boiling water (Iowa State; University of Kentucky).
- Rinse bottles and cans before they go in the recycling, and wash out the bin (University of Kentucky).
- Wash or replace mops, sponges and rags, and let them dry (University of Kentucky).
- Seal home-canning and fermenting jars and fit tight 16-mesh window screens (University of Kentucky).
Sprays only kill the adults present at the time — "only a temporary relief at best" (Iowa State) — while new flies keep coming from the source.
How this fruit fly die-off calculator works
The calculator uses Da Lage and colleagues' 1989 equations for average survival with no food, separately for males and females, at your temperature (11–31 °C). "Last adults" takes the longer-lived sex's average and adds two standard deviations, using the largest variation the study reported (29%). If you're sure the source is gone and you've ticked every common spot, the date is the removal date plus that survival time. If you're not sure, or some spots are unticked, it adds the egg-to-adult time at your temperature (Bloomington Drosophila Stock Center), because eggs may already be developing somewhere you haven't checked. If the source is still there, the status is "Still breeding — find the source". Removal dates in the future are rejected.
All figures are best cases for a home with no food left at all; any leftover sugar or fermenting residue will keep flies going longer.
Frequently asked questions
How long can fruit flies live without food?
About two to three days at room temperature: average survival with water but no food is 63–70 hours at 21 °C and 46–51 hours at 25 °C (Da Lage et al. 1989).
How long does it take for fruit flies to die?
About 4.6 days at 21 °C once every food source is gone. If eggs may still be developing elsewhere, allow about 17.6 days.
Will fruit flies go away on their own?
Sometimes, if the source was a single piece of fruit that's now gone (Iowa State). If they're breeding in a drain, bin or forgotten vegetable, they'll keep coming.
How long does it take to get rid of fruit flies?
About 4.6 days at 21 °C once every breeding spot is gone, while the last adults die without food (Da Lage et al. 1989). Allow about 17.6 days if eggs may be developing somewhere you haven't checked.
Why do I still have fruit flies after throwing out the fruit?
Because they are breeding somewhere else — usually a drain, garbage disposal, recycling bin, mop or rag. New adults appear about 9–19 days after eggs are laid, depending on temperature.
How long do fruit flies live without food and water?
Less than a day at room temperature: about 21–27 hours at 21 °C in dry air (Da Lage et al. 1989).
How long do fruit flies last in a house?
A few days after the last breeding source is gone. With a source, they can last indefinitely, because new adults keep replacing the old.
How long will fruit flies live without food?
On average 63–70 hours at 21 °C if they can find water, and about 36–40 hours at 28 °C; a few last a day or so longer than average (Da Lage et al. 1989).
Does temperature change how long fruit flies survive without food?
Yes. With water but no food, adults average 100–114 hours at 15 °C, 63–70 hours at 21 °C and 36–40 hours at 28 °C (Da Lage et al. 1989). Cooler flies use their reserves more slowly.
How long until fruit flies go away?
Usually within a week of removing every breeding spot at room temperature. Traps speed up the last few days.
How do I get rid of fruit flies fast without chemicals?
Remove or refrigerate ripe produce, clean drains and bins, wash mops and rags, and catch the rest with a cider-vinegar trap (University of Kentucky).
Can fruit flies breed in drains?
Yes. They breed in the slime above the water line in slow or seldom-used drains. Tape plastic over the drain overnight to check (Iowa State).
These calculators give estimates for education. Real flies vary with strain, food, humidity and temperature. For a stubborn infestation, your local cooperative extension service can help identify the insect. We give no pesticide advice.