If you have rats in the house or garden and cannot find how they are getting in, the drains are a common answer. Rats live in sewers, swim well and can travel along pipes. A break in a drain gives them a way out.
Signs rats may be coming from the drains
- Scratching in walls, under floors or in boxed-in pipework, often at night
- Droppings near drain covers, gullies or under sinks
- Burrows or holes in the garden close to a drain run
- Gnawed wiring, insulation or food packaging
- Rats seen near inspection chambers or gullies
- Repeated rat problems even after treatment, with no obvious entry point
How rats get in through drains
- Broken or cracked pipes, where rats can dig out into the soil and up into gardens or under floors.
- Displaced joints, common in older clay drains.
- Old connections that were never capped, for example where a toilet or sink has been removed during building work and the pipe left open under the floor.
- Damaged chambers, with missing bricks or broken benching.
- Missing stoppers in interceptor traps, which can give rats a route from the sewer. See what is an interceptor trap?
Finding the entry point
Poison and traps deal with the rats, but not the route. A CCTV drain survey shows breaks, open joints and uncapped connections, so the defect can be found and fixed. Smoke testing is another method sometimes used to find openings in a drainage system.
Common fixes
- Repairing the damaged section of drain. See drain repairs.
- Capping redundant pipes properly.
- Repairing damaged chambers, and replacing missing stoppers or covers.
- Rat blockers: one-way flaps fitted in the drain that let waste out but stop rats coming back up. These are widely used where rats come from the sewer. They need checking from time to time so they do not cause blockages.
Dealing with the rats themselves
For the rats already in or around the property, contact a pest controller or your local council’s pest control service. Dealing with the drain defect at the same time makes it far less likely they return.
Is it my responsibility?
You are usually responsible for drains that serve only your property within its boundary. Shared drains and public sewers are generally the water company’s responsibility. See who is responsible for a shared drain and signs of a broken drain pipe.