A cockroach keeps coming up my drain. How do I stop it?

Large cockroaches in sinks, showers and floor drains usually come in from pipes and outside rather than breeding in your cupboards. Cover the drain at night, keep water in the trap, seal around pipes and put bait stations nearby.

Cockroaches 3 min read Updated 9 October 2026

Watching one climb out of the sink is horrible. If it is a big one, there is a likely explanation: large cockroaches in drains are usually American or oriental, coming in from pipes, sewers and outside. They are more often visitors than a colony living in your cupboards. You can turn the drain into a closed door, mostly with things you already have.

Which one is it?

Large and reddish, with a pale band around the shield behind the head and long wings: American.
Shiny and nearly black, with short wings or only stubs: oriental. Likes cool, damp spots, ground floors and cellars.
Small and tan with two dark stripes behind the head: that is a German cockroach. It lives indoors and only visits the sink for water. Different plan, see is it a German cockroach.

Why bleach does not stop them

Bleach poured down the drain rushes straight past. It does not stay in the places cockroaches shelter: the pipe joints, the gap where the pipe meets the wall, the space behind the bath panel. Flushing water or spraying deodorant has the same problem. A few seconds of contact, then gone, and the next one walks up the same way.

Bleach is also risky to use this way. Never mix it with other drain cleaners or products, because some combinations give off dangerous fumes.

Close the door

Cover the drain at night. Put the plug in, or fit a drain cover or a fine mesh strainer. Keep the toilet lid down.
Keep water in the trap. The U-shaped bend under a sink or shower holds water that blocks the pipe. In a drain you rarely use, a spare bathroom or a floor drain, that water can dry out and leave the pipe open. Run the tap in those every week or so.
Fix leaks and damp. A dripping trap or a wet cupboard under the sink is exactly what these cockroaches look for.
Seal around pipes where they come through the wall or floor, under the sink and behind the bath panel. See sealing gaps.
Bait stations near the drain. Closed bait stations suit the larger cockroaches. Put them in the cupboard under the sink and beside the bath or shower, and follow the label.
Put a monitor trap beside it and check it weekly, so you know whether the visits are stopping. See how to use monitor traps.

Kids and pets: bait stations and traps go somewhere a child or pet cannot get into, such as inside a closed cupboard or behind the bath panel. If a label says to keep the product away from children or pets and you cannot, leave it out.

New flat, and they are in every sink

If you have just moved in and you see them in the sinks and the toilet, tell your landlord in writing straight away, with dates and photos. Cockroaches coming up several drains at once can point to a building problem: broken pipe seals, dry traps in an empty flat nearby, or damaged drains outside. That is a job for the landlord and a plumber, not something you should have to fix alone. Our answers on just moved in and found pests and what to send your landlord help with the message.

When to get help

If they keep coming after the drains are covered at night and the gaps around the pipes are sealed, or you start seeing them in other rooms, call a pest controller, and a plumber if you suspect a damaged pipe. Seeing big dark ones in the kitchen at night too? Read big dark cockroach at night.