Can Rats Climb Drains, Toilets and Sewer Pipes?
It sounds unbelievable, but yes — rats can climb drains, sewer pipes, vertical pipework and even get into buildings through toilets and drainage systems. Thankfully rats coming out of a toilet is fairly rare.
Drainage systems however are one of the most common causes of long-standing and repeat rat infestations that we deal with.
Many people assume rats are simply entering through holes in walls or gaps around doors. While this does happen, persistent rat problems often originate underground through damaged or faulty drainage systems.
Why Do Rats Live in Drains?
Rats living in drains is completely normal behaviour.
When we lift inspection covers during surveys, it is extremely common to find:
- Rat droppings
- Smear marks
- Nesting material
Why? Because drains provide almost perfect living conditions for rats:
- Predator-free environments
- Constant access to water
- Regular food sources from waste and sewer systems
- Warm, sheltered underground spaces
If rats remain entirely within the drainage system, they do not always create problems above ground. However, the issue starts when they find routes out of the drains and into properties.
Drain faults are one of the most common causes of repeat rat infestations in homes and commercial buildings.
Can Rats Climb Vertical Pipes?
Yes — surprisingly easily.
Rats are extremely agile climbers and can travel significant distances through underground pipework before climbing vertically inside rainwater downpipes and 4-inch soil stacks.
Rats are incredibly agile, and are able to climbing internal pipe surfaces with ease. I wouldn’t have believed it myself if I hadn’t seen it on video. Not only did the rat climb vertically the inside of a 100mm/4 inch pipe, when it saw the camera it turned around!
This can allow rats to reach our roof spaces and lofts. This can then lead them to;
- Enter cavity walls
- Access ceiling voids
- Get behind kitchen units
- Appear beneath baths or inside boxed pipework
This is why some rat infestations seem to “appear from nowhere,” especially in properties where no obvious external entry point can be found.
How Rats Get Into Buildings Through Drains
More commonly than climbing pipe vertically, rats follow sewer lines until they reach:
- Broken drains
- Cracked pipe joints
- Redundant pipework
- Uncapped drains
- Displaced connections
Once rats locate a drainage fault, they can burrow into the surrounding ground and enter the structure of the building itself.
From there, they often move into:
- Floor cavities
- Wall voids
- Loft insulation
- Service ducts
- Behind fitted kitchens
- Under baths and shower trays
This is why some rat infestations continue for months or even years despite repeated treatments, and no obvious signs where they are coming from.
If the underlying drain issue is not identified and repaired, the infestation often returns.
Can Rats Come Up Through Toilets?
While less common, yes — rats can occasionally enter properties through toilets, swimming through the trap at the back of the toilet. But in the years I have been in the industry I have yet to see this on a job.
Where rats are entering through soil stacks or toilet systems, a rat drain valve may be required.
These one-way valves are fitted within the drainage system and help prevent rats from travelling further upstream toward the building. These are best installed by an experience installer, given their use is subject to the legal ownership of the drains.
How Can You Stop Rats Getting in Through Drains?
The correct solution depends on how the rats are entering.
Rainwater Downpipes
If rats are climbing external rainwater pipes, fitting guards at the top of the pipe can prevent roof access.
Soil Stacks and Toilets
Where rats are moving through sewer systems or accessing toilets and internal pipework, rat drain valves are often the most effective solution.
Drainage Faults
If a drainage issue is suspected, a full CCTV drain survey should be carried out.
This allows the drainage system to be inspected internally so faults can be identified accurately.
Once located, the correct repair solution can then be recommended.
Why Drain Faults Are So Common
Drain faults happen naturally over time through:
- General wear and tear
- Ground movement
- Ageing pipework
- Root ingress
However, we also regularly find drainage issues caused during building alterations.
Extensions, kitchen renovations, garage conversions and drainage changes sometimes leave old pipe runs unsealed or improperly capped.
Unfortunately, builders are not always considering the pest control implications of drainage work — which can unintentionally create direct access routes for rats.
If Your Pest Controller Never Mentions Drains, That’s a Concern
If you are repeatedly having rats treated but the problem keeps returning, the drainage system should absolutely be considered.
Drain faults are one of the most common entry routes into properties.
If there is:
- No obvious external entry point
- Ongoing repeat infestations
- Rats appearing internally
- There has been building alterations on the property or neighbours.
there is a strong possibility the issue may originate from the drains.
Simply placing bait without investigating the root cause often leads to recurring infestations.
How The Pest Company Can Help
At The Pest Company, we take a long-term approach to rat control rather than simply treating the symptoms.
We can help by:
- Confirming the species causing the issue
- Putting an effective treatment plan in place
- Investigating likely entry routes
- Identifying whether drainage faults may be involved
- Carrying out CCTV drain surveys where required
- Recommending proofing and repair solutions to prevent recurrence
Our aim is not just to reduce activity temporarily, but to help solve the root cause of the infestation.
Rat Control and Drain Investigations Across Yorkshire, Teesside, Cambridgeshire and Essex
We provide professional rat control, proofing and drain-related pest investigations across:
If you are dealing with repeat rat problems, scratching in walls or lofts, or suspect rats may be entering through the drains, contact The Pest Company to arrange a survey and treatment plan.
