The essentials in 30 seconds
To get rid of cockroaches: identify the species, put sticky traps out for a few days to find where they gather, place gel bait in small dots in those spots (cupboard hinges, behind appliances, around pipes), remove food and water, seal cracks and pipe gaps, and keep monitoring for 3 to 4 weeks. Baits are slow on purpose: expect results after 7 days or longer. If catches have not fallen by week three, call a pest control professional.
- Small, light brown cockroaches in the kitchen are almost always German cockroaches, which breed indoors and need baiting.
- Large, dark cockroaches near drains are usually oriental or American cockroaches, which come in from drains and outside and need sealing.
- Avoid sprays alongside baits: sprays repel cockroaches and they then avoid the bait. Foggers miss the hiding places.
Which cockroach do you have? German, American and others
Knowing the species changes the strategy, because each one lives in different places and breeds at a very different speed.
| Species | What it looks like | Where it lives | Breeding speed |
|---|---|---|---|
| German cockroach (Blattella germanica) | Small, about 1.3 cm, light brown with two dark stripes behind the head | Kitchens and bathrooms: inside units, dishwashers, cookers, fridge motors | Fastest: one female and her offspring can produce over 30,000 a year |
| Brown-banded cockroach (Supella longipalpa) | Small, about 1.3 cm, with light bands across the wings and body | Drier rooms: behind pictures, inside electrical appliances, furniture | Over 600 a year; egg cases glued under furniture |
| Oriental cockroach (Blatta orientalis) | About 3 cm, black or very dark brown, shiny; short or stubby wings | Drains, cellars, cool damp areas; often enters at ground floor | Nearly 200 a year; can take one to two years to reach adulthood |
| American cockroach (Periplaneta americana) | Large, about 5 cm, reddish brown with pale edges on the shield behind the head | Sewers, boiler rooms, warm cellars | Over 800 a year |
German vs American cockroach: what the difference means for you
| Feature | German cockroach | American cockroach |
|---|---|---|
| Size | About 1.3 cm | About 5 cm |
| Colour | Light brown, two dark stripes | Reddish brown, pale edge behind the head |
| Where it comes from | Lives and breeds inside the home; arrives in boxes, bags and second-hand appliances | Lives in sewers and drains; comes up through dry traps and damaged pipes |
| Egg case | Light beige, about 30 young; the female carries it until it is about to hatch | Brown turning black, about 12 young; the female glues it in a sheltered spot |
| Main fix | Gel bait in many small dots, cleaning, monitoring | Sealing drains and gaps, drain covers, baits at entry points |
| Seeing one means | Probably more hidden nearby: set traps | Possibly a stray from the drains, especially in summer |
Because a German cockroach female carries her egg case until it hatches, the eggs are protected from most treatments. That is why baiting has to continue for several weeks, until every hatched nymph has fed on the bait.
Signs of a cockroach infestation
- Droppings like ground pepper, or dark smears, in drawer corners, on hinges and behind appliances.
- Egg cases: brown, oblong capsules a few millimetres long.
- Shed skins or dead cockroaches.
- A musty, oily smell in closed cupboards.
- Cockroaches out during the day: a sign of a large population.
- In the bath or sink: oriental cockroaches often get trapped there because they cannot climb smooth surfaces.
How to find where cockroaches hide with sticky traps
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01
Set at least ten traps
Put them against walls and in corners: next to the fridge and cooker, under the sink, behind the dishwasher, in cupboards and drawers, and by the bathroom pipes.
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02
Number each trap
Write a number and the place on each one, so you can compare catches.
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03
Check daily for a few days
Many cockroaches are caught in the first 24 hours. Note the count on each trap.
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04
Read the results after a week
The traps with the most catches mark the hotspots, and those are where the baits go.
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05
Keep a few traps as monitors
Replace them as they fill and use them to measure progress through the treatment.
| What you catch | Likely situation | What to do |
|---|---|---|
| Many small nymphs and adults in the kitchen | German cockroaches breeding indoors | Gel bait in the hotspots; full four-week plan |
| One or two large dark adults near a drain or door | Oriental or American cockroaches coming in from outside | Drain covers, keep traps full of water, seal gaps |
| Catches in several rooms, egg cases under furniture | Brown-banded cockroaches | Professional help: they respond poorly to baits |
| Catches on every floor of a block of flats | Shared infestation | Building manager and a coordinated treatment |
How to get rid of cockroaches step by step
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01
Day 1: deep-clean the kitchen
Remove grease behind the cooker and oven, crumbs from drawers and debris under the fridge. With no other food around, baits work much better.
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02
Day 1: remove water sources
Fix dripping taps and traps, dry the sink at night and avoid leaving pet water bowls out overnight where possible.
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03
Days 1 to 3: set the sticky traps
Use them as described above to find the hotspots.
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04
Day 3: apply gel bait
Small dots, the size of a lentil, in cracks, cupboard hinges, around pipes and behind appliances, out of reach of children and pets. Many small dots work better than a few large ones.
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05
Throughout: skip the sprays
Aerosol insecticide contaminates the bait and makes cockroaches avoid it. To deal with a single cockroach, squash it or catch it on a sticky trap.
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06
Week 1: check and top up
Look at the baits and replace any that have been eaten. Results usually show after about a week: cockroaches that eat the bait carry it back to the others.
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07
Week 2: seal entry points
Fill cracks in skirting boards, gaps around pipes under the sink and around sockets and frames with silicone or filler.
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08
Week 2: protect the drains
Fit grilles or covers on floor drains, run water in rarely used drains so the traps stay full, and check the seal around the toilet.
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09
Weeks 3 and 4: monitor
Keep the sticky traps in place. If catches have not dropped by week three, call a professional.
What works and what does not
| Method | Use | Limits |
|---|---|---|
| Gel bait | Kills cockroaches that eat it and others in the hiding place | Needs 1–3 weeks and no competing food |
| Bait stations | Same as gel, safer with children and pets | Place several, in the right spots |
| Boric acid dust | A thin film in dry, undisturbed voids | Loses effect when damp; slow, 7 days or more; toxic if swallowed |
| Diatomaceous earth | Dust barrier in dry gaps | Slow; poor in damp areas |
| Aerosol spray | Kills cockroaches you can see | Repels, scatters and misses the eggs |
| Fogger or bug bomb | Not recommended | Misses hiding places; leaves residue around the home |
| Ultrasonic devices, bay leaves | No proven effect | They do not clear an infestation |
About boric acid: use it as an almost invisible film under appliances and inside voids, not in heaps, because cockroaches avoid visible piles. Keep any home-made mixture with sugar or flour inside closed containers out of reach of children and pets.
Common mistakes that keep cockroaches around
- Spraying the kitchen the day after laying baits.
- Putting bait in one or two big blobs instead of many small dots.
- Placing bait in the middle of shelves instead of in cracks, hinges and corners where cockroaches rest.
- Leaving grease, crumbs and pet food out, so the bait has competition.
- Stopping after the first week, before the eggs have hatched.
- Ignoring the neighbours: in flats, cockroaches move through shared pipes and ducts.
How to keep cockroaches away
- Store food in airtight containers, including pet food.
- Take the rubbish out daily and use bins with lids.
- Wash up before bed instead of leaving dishes overnight.
- Avoid piling up cardboard and paper bags: they shelter and carry cockroaches.
- Check removal boxes, second-hand appliances and deliveries before bringing them in.
- Keep drain traps full of water and grilles in place.
- Fix leaks and damp under the sink.
- In blocks of flats, tell the building manager: if they come from shared areas, treatment needs to be coordinated.
When to call a pest control company
Call a professional if you still see cockroaches after 3 to 4 weeks of baiting and cleaning, if you see them in daylight or in several rooms, if you suspect brown-banded cockroaches, if you run a food business or if the source is in shared areas of the building. A good service inspects first, explains which products it will use and where, gives safety intervals for people and pets and includes at least one follow-up visit. Modern treatments rely mainly on gels and bait stations, not on spraying the whole home.
Cockroaches: frequently asked questions
What is the most effective way to get rid of cockroaches?
Gel baits or bait stations placed in their hiding places, combined with cleaning, removing water and sealing cracks. Sprays only kill the ones you see.
What are the small brown cockroaches in my kitchen?
Almost certainly German cockroaches: about 1.3 cm, light brown, with two dark stripes behind the head. They breed indoors, so bait them and keep monitoring for several weeks.
What is the difference between German and American cockroaches?
German cockroaches are small, light brown and breed inside kitchens. American cockroaches are about 5 cm, reddish brown and come from sewers and drains.
Can cockroaches fly?
A few species fly short distances or glide on warm nights, such as smokybrown cockroaches and brown-banded males. Oriental cockroaches cannot fly, and German cockroaches are usually seen running.
Are cockroaches dangerous?
Their droppings and shed skins can trigger allergies and asthma, and they can carry bacteria on to food. That is reason enough to deal with them quickly.
How long does it take to get rid of them?
With well-placed baits, numbers usually drop after one or two weeks. Keep going for three to four weeks to catch newly hatched nymphs.
Why do cockroaches come up through the drain?
Large species such as the oriental and American cockroach live in drains and sewers. Keep traps full of water, fit drain grilles and tell your neighbours if they appear on several floors.
Does one cockroach mean an infestation?
Not necessarily, especially a large one near a drain in summer. A small one in the kitchen is worth checking with sticky traps.
Sources
Official and university guidance, checked on 26 October 2026. Use only authorised products and follow the label.
- University of California IPM · Cockroaches ↗Species, sizes, egg cases, breeding rates, flight, health concerns, sticky traps, baits, boric acid and why to avoid foggers.
- Penn State Extension · German cockroaches ↗Egg capsules, development, sticky trap surveys with ten or more traps for a week, sanitation and why sprays and foggers are of little value.
- US EPA · Dos and don'ts of pest control ↗Safe use of insecticides and integrated pest management.
- Real Decreto 1054/2002, biocides (BOE, Spain) ↗Article 27: register of pest control companies (ROESB).
Still seeing cockroaches?
Keep the monitoring traps and note where and when you see them before asking for a quote.