Expert warns rats are invading UK homes in ‘ignored underground motorways’

A drainage expert has warned that hidden drain faults are a leading cause of rat infestations -- and that treating above ground is rarely the answer

07:00, 05 May 2026

This could be channelling rats into your home at speed(Image: Getty)

A plumbing and drainage specialist said one frequently overlooked problem[1] enables rats to use pipework as "underground motorways" to infiltrate homes across the UK.

Hidden drain defects are amongst the leading causes of rat infestations in British homes, and uncertainty over who bears responsibility for repairing them is significantly worsening the situation.[2]

Jack Cox, Managing Director and Founder of Bromley Plumbers, reports that he receives call-outs for rat-related drainage problems once or twice weekly.

With spring well underway and summer on the horizon, he cautions that milder weather[3] will drive rat activity upwards, and that numerous homeowners are investing money in entirely the wrong solutions.

"Rats are experts at finding safe routes in and out of properties," Cox said. "Drains and sewer pipes are like underground motorways for them.", reports the Express[4].

Rats can use pipes as under-gound motorways(Image: Getty)

They navigate through pipework, travel between properties, and emerge wherever they discover a vulnerability, whether that's a fractured pipe, a compromised manhole cover, or an opening around a drain.

The fundamental problem, according to Cox, is that most people address what's visible rather than what's causing the issue beneath the surface.

Sprays, deterrents, and surface-level pest control seldom address the underlying cause when the genuine fault lies metres underground within a damaged drain or sewer pipe. Cox recalled one particular case that has remained with him.

A homeowner in Beckenham, Kent, had rats appearing throughout her property, in the bathrooms and even emerging near the bath.

Over a period of time, the rodents had gnawed through three separate toilet waste pipes.

Upon further investigation, his team uncovered a damaged communal drain approximately eight metres underground, which was enabling rats to move freely throughout the shared system.

"The frustrating part was that because it was a shared drainage issue, there were delays and arguments between the parties involved over who was responsible for fixing it," Cox explained.

There is a hidden way rats could be getting into your home(Image: Getty Images/iStockphoto)

This dispute meant the problem remained unresolved for far longer than it ought to have been, with the infestation persisting throughout.

This case highlights a predicament that countless homeowners encounter without even being aware of it. Establishing who actually owns a drain is not always a clear-cut matter, and getting it wrong can mean either forking out for repairs that aren't your responsibility, or waiting on others while rats continue to roam through your home.

Cox sets it out plainly.

If the damaged drain solely serves your property before connecting to the public sewer, the responsibility for repairing it generally falls to you as the homeowner.

Should the fault lie within a shared drain or communal sewer, however, the local water company takes over. For much of the area his team operates in, this means Thames Water handling shared sewer problems.

This clarification is supported by Ofwat guidance on pipe and drain responsibility, which states that drains and private sewers carrying household waste are typically the householder's responsibility up to the point where they join the public sewer.

Beyond that point, responsibility transfers to the sewerage company. Shared drains, which serve multiple properties, involve joint responsibility between the relevant property owners, which is exactly what makes disputes such as the one Cox outlined so protracted.

Make sure you treat problems that might not be visible(Image: Getty Images)

"We are often asked who is responsible for rats in drains and rat-related drain faults, and the answer depends on where the defect is," Cox said.

"A good plumber or drainage engineer should be able to help you work out whether the drain is private or shared, where the damage is likely to be, and what your next step should be."

Obtaining clarity on this early isn't merely practical guidance. Cox is forthright about the cost of getting it wrong. "Getting clarity early can save a lot of stress and wasted money."

For homeowners experiencing recurring infestations who have already attempted pest control without success, Cox's recommendation is to have the drainage inspected before spending further money on deterrents.

A CCTV drain survey can pinpoint damage, blockages or structural defects that provide rats with a route into the property, and it can establish whether the fault lies on private or shared infrastructure before any expenditure is incurred.

The timing is significant.

Rodent activity increases as temperatures rise during the summer months, which means any drainage issue left unexamined now is likely to develop into a more severe problem come July and August.

Pinpointing the origin of the issue, and establishing precisely who is responsible for addressing it, offers the most straightforward path to solving an infestation that repeatedly returns.

References

1. ^ overlooked problem (www.walesonline.co.uk)
2. ^ significantly worsening the situation. (www.walesonline.co.uk)
3. ^ weather (www.walesonline.co.uk)
4. ^ the Express (www.express.co.uk)