The pattern we see every year
Between June and October our cockroach callouts across Bengaluru roughly double, and the complaints follow a script. The kitchen was fine all summer. Then the rains set in, and within a fortnight there are roaches on the platform at night, in the sink cabinet, sometimes running across the floor in daylight.
The households calling us have not changed how they clean. What changed is outside the flat: the drains, the humidity and the temperature. Cockroaches respond to those far more than to crumbs.
What the rain actually changes
Three shifts happen at once, and they compound.
- Storm drains flood. American cockroaches — the large reddish-brown ones — live in sewer and stormwater lines, not in your kitchen. When those lines fill, the population is pushed upward through drain traps, floor outlets and the gaps around pipe sleeves. Ground-floor flats and older buildings see this first.
- Humidity climbs and stays there. Bengaluru sits at 80-90% relative humidity for weeks at a stretch during the monsoon. Cockroaches lose water quickly and need damp harbourage; a kitchen that was too dry for them in April becomes comfortable in July.
- Breeding speeds up. German cockroaches, the small pale-brown ones that live indoors permanently, complete their cycle faster in warm, humid conditions, so numbers invisible in May become obvious by August.
The practical consequence is that a monsoon infestation usually has two separate sources: one that walked in from the drain, and one that was already breeding quietly indoors. Treating only one of them is why people find the problem comes back.
Which cockroach you have matters
Before you do anything, work out which one you are dealing with, because the fix is different.
- Large, reddish-brown, appears near the drain or bathroom at night. American cockroach, coming from the building line. Your problem is an entry point, not a kitchen hygiene issue.
- Small, tan, with two dark stripes behind the head, always in the kitchen. German cockroach, breeding indoors. Nothing you do at the drain will touch it.
A quick test: if you only see them after dark near a floor trap, it is the first. If you switch on the kitchen light and several scatter from the platform, it is the second.
What to do in the first week
These steps cost nothing and make a real difference before any treatment.
- Cap every floor drain. A cheap mesh or a rubber drain cover on the utility, bathroom and kitchen outlets blocks the single most common monsoon entry route. Keep them on overnight, when movement peaks.
- Seal the gap around pipe sleeves. The ring gap where the AC copper pipe or the sink waste passes through the wall is a doorway. Steel wool packed in and sealed over works.
- Dry the kitchen down at night. Empty the sink, wipe the platform, fix a dripping tap and take the bin out. Cockroaches can go a long time without food and a short time without water, so removing moisture matters more than removing crumbs.
- Degrease, do not just wipe. The film behind the gas stove and inside the chimney housing survives ordinary cleaning, and it makes bait less attractive later.
- Ventilate. Run the exhaust fan after cooking and open the utility window when the rain lets up. Cutting the humidity in the kitchen makes it measurably less hospitable.
Two things that usually make it worse
Spraying everything you can see. A general-purpose aerosol kills what it lands on and does nothing to the population in the cavity. Worse, in a German cockroach infestation it scatters the group into adjacent rooms and cabinets, turning one problem area into three. It also contaminates surfaces where bait would otherwise have worked, which makes professional treatment slower.
Relying on a smoke or fumigation can. Same logic: knockdown without residual effect, plus dispersal. We are regularly called to homes where a shop-bought bomb has spread a kitchen infestation through a whole flat.
If you do nothing else, avoid spraying the areas where cockroaches are actually harbouring. Gel bait works precisely because they keep using those spots.
When it is worth calling someone
A handful of large cockroaches near a drain, with no daytime sightings, is usually solvable with drain covers and sealing. It is worth booking a treatment when any of the following is true:
- You see cockroaches during the day, which normally means the harbourage is crowded.
- You find egg cases — small brown capsules glued behind the fridge compressor or inside cabinet hinges.
- They are small and striped, which means they are breeding indoors and will not leave on their own.
- The problem returns within a week or two of cleaning and sealing.
- You live in a tower and neighbours report the same thing, which points to the shared riser.
That last one matters in Bengaluru specifically. In the gated developments around Whitefield, Bellandur and Sarjapur Road, German cockroaches move between flats along common plumbing shafts. Treating one kitchen in an affected stack buys a few weeks; treating the affected flats together is what actually holds.
What professional treatment involves
For a monsoon infestation we usually run gel baiting as the main method, with a residual spray at the drain mouths and perimeter where an American cockroach problem is coming up from below. Baiting is slower than a heavy spray — you should expect numbers to fall over one to two weeks rather than overnight — but it reaches the insects in the cavity that you never see, which is the part that decides whether the problem returns.
Afterwards the useful habits are the boring ones: keep drain covers on through the season, keep the kitchen dry overnight, and leave treated cabinet interiors unwashed for a week.
If you want the detail on how the treatment runs, what it costs and how the warranty works, that is all set out on our cockroach control page for Bangalore.