BPCA news archive

13 September 2017

Rats underfoot; drainage engineer or pest control technician?

Feature pest control crossover | PPC88 September 2017

What do you do when you suspect a rodent’s route of entry is from a flaw in the inaccessible pipes beneath your feet? We asked drainage expert, Mick Grant from BPCA Associate Member company, MG Drainage, to give us an insight into the potentially draining problem of rats in pipes.

rats underfoot banner

Speed view

The surveys that we undertake as a result of rodent activity have increased over the last few years. Generally, these jobs come to us from recommendations made by pest control technicians after they’ve done a site survey, but we also get enquiries directly from the general public through our website.

It’s a given that rats live in our main sewer systems and the connecting pipes are easy paths for them to follow and explore. We all know what they’re looking for and once they find it, they can settle in and usually survive safely. While it’s fairly easy for rodents to find these tiny paths, it’s not so easy for the professionals to find the rats or even prevent them.

For the unfortunate people that have to suffer rodents living in their pipes, who should they contact? The first thing that most people will think about when faced with rodents is pest management professionals – and why should they think any different? People aren’t aware of the problems that can be caused by a defective or poorly installed drainage system, and therefore wouldn’t necessarily think about us… that is, until it’s too late.

Identifying the problem

Pull quote 1 rats underfoot

Once we attend a site, we are usually following someone who has already checked the obvious, started a baiting programme and found evidence that the below-ground drainage system is the source of rodent activity (or that there isn’t any other feasible explanation).

One of the first questions we will ask during an enquiry or when arriving at a new site is this: has there been any building work undertaken, recently or otherwise? Even works completed a few years previously can be evidence of rodent activity, especially if the position of activity is around the area of work. This is the most common source of rodent activity we encounter and typically the cause is a redundant pipe, an access point or branch that has been left in the ground without being sealed. However, there are some jobs that require a bit more thought and a detective-like approach, eliminating the obvious to eventually show proof for the area of concern.

The kit that separates us

There are certain things that we can do that the pest management guys cannot (and vice versa). A big tool in our arsenal is CCTV cameras. Now, there’s nothing to stop pest controllers from purchasing camera equipment so they can offer this service – after all, this is another string to your bow, so to speak. It could be the piece of kit setting you apart from your competitors who don’t have the facility. Surely pushing a camera up a pipe is not rocket science?!

However, it’s not quite that simple. You do have to have an understanding of what to expect and where the camera is going or likely to go. It’s very easy to get your expensive, new equipment stuck on bends, on displaced joints or on a dimension change – especially with an inexperienced operator. Stuck equipment can be costly to remove.

Inexperience aside, the cost of a decent bit of equipment is high and it has to be used a lot to justify the expense.

Small ‘look-see’ cameras are available for much less and in some cases these can work quite well, but there are limitations to what they can do. Generally, they won’t do exactly what you’d hope of them. Drawbacks include poor quality of picture, insufficient lighting and reliability issues, to name but a few.

midfooter rats

Risks when opening a drainage system

Drainage systems are restricted, can be dangerous and most are confined spaces. Gas detectors to monitor the quality of the air should be always be used. Although this might be common sense to many professionals, there aren’t actually any safeguards in the industry to prevent anybody from getting a set of manhole keys and calling themselves a drainage engineer.

The sector isn’t monitored or regulated and there are no specific requirements, although the National Association of Drainage Contractors (NADC) is working hard to change this. If you do need to locate a drainage engineer in any part of the country, I’d recommend starting here.

While working with drains is unregulated, obtaining professional baits and chemicals used in pest control is far stricter, which I personally think is great for everyone. Regardless of the industry, you have to know what you are doing and be trained correctly before doing something potentially dangerous.

Putting a plug in it

If you actually detect a defect in a pipe, you need to have the facilities to offer a remedy – and with drains, it’s usually a remote fix.

Open pipes are rarely accessible unless you want to start excavating slabs or removing floors. Techniques such as lining or using manoeuvrable sealing bags are much better solutions for stopping rats getting into cosy pipework. This equipment is highly specialised and, again, comes at an expense.

Rat damage to drain cover

Case study

The call out

Rodent activity was reported inside a groundfloor false ceiling next to a kitchen, which later spread to the loft where rats were trapped and caught. A pest technician had done a survey and hadn’t found anything obvious, leading to suspicions of a below-ground drainage defect.

The survey

We were called for an opinion and to investigate the drainage system. After a CCTV survey we found a buried manhole chamber below a tiled kitchen floor sitting directly below an Aga cooker. In this chamber there was therefore a potential access point for rodents to exit the drainage system and access floor and wall voids.

The treatment

Obviously, removing an Aga and breaking up a kitchen floor was to be avoided due to the cost and inconvenience. Instead, we installed a liner (a pipe within a pipe) through the main pipe which effectively sealed off the chamber, eliminating the obsolete branch, leaving it as a through flowing pipe section. This process can usually be completed and the liner cured in a few hours meaning the drainage system is operational within a short space of time.

The drain liner being prepared prior to installation. It is made of polyester, so it stores flat and flexible. The liner is impregnated with resin, once installed and inflated to the host pipe the resin cures and solidifies.

Follow up

Once installed, activity stopped and this was thought to have solved the issues. However, we were then called back a few weeks later due to fresh activity being noticed.

We re-inspected the drainage system and the liner previously installed to find this was still satisfactory. We then discovered that a plastic gully grid for an external raw waste pipe had a hole in it. On closer inspection we found it had been chewed through from the underneath - suggesting it had been used by rats for an exit point.

We assume that once the liner had been installed, rats may have been trapped inside the property and they had been forced to find another exit through the gully grid. The plastic grid was removed and a metal one fitted and this was the last we heard of it.

Pull quote 3 rats underfoot

So, weighing it all up, there probably is a requirement for both a professional pest controller and a professional drainage contractor when dealing with certain rodent problems. There is an argument that calling a pest control technician first is the best option based on economics. Why go to the the expense of having a drain survey completed until there is some justification to do so?
If pest management can treat the rats, some customers may not care about the source. However, it is the job of the pest control technician to educate their customers and advise that the source needs to be proved and prevented. A route used and left can easily be found again and rodent problems can return.

We see it as our job to recommend pest management for the purpose of professionally controlling and eradicating pests – maybe pest technicians should be aware of the professional services a drainage contractor can provide too.

Hopefully, you can see that there are different skills for each trade and each trade can be as important as the other. Our trades docrossover in the middle. Ultimately, using both a professional pest controller and a drainage contractor will give the best results.

7 things to remember when working around drains

  1. Always wear gloves and keep working area around drains clear and clean. Wear overalls where needed and wash your hands and equipment thoroughly after use
  2. Ventilate the drainage system wherever possible. If you have to lift one cover, lift another up or downstream to allow ventilation
  3. Drainage systems can be shared and as such could be a local water authority asset
  4. Never enter any manhole chamber. Even leaning into one with your head below ground is very dangerous
  5. Drainage systems can be dangerous environments with a lack of oxygen, harmful gases and even the risk of explosions. Never smoke over an open chamber
  6. Never leave open manholes or inspection chambers unattended. You may know where they are but the postman doesn’t!
  7. Manhole covers can be heavy, especially block infill covers on driveways. They should be raised square directly upwards. Sometimes you may need mechanical lifting equipment to raise these


Get over to NADC’s website to find a reputable drainage contractor...

NADC online

Take the CPD quiz now (Login required)

< Contents Next article >

Mick Grant authorMick Grant
MG Drainage

15 September 2017  |  PPC88

Source: PPC88