Rats and Drains
You may or may not be aware but rats live in the main sewage / drainage network and can often find their way out of this through various ways, into your property. They can be found in both the foul and surface water drainage systems.
Drainage defects account for around 70% of the rat jobs we attend.
Often we find that alterations to drainage systems, such as when new kitchen extensions are built, or when drainage systems are adapted or altered, the work carried out may not be of a sufficient standard to prevent rats exiting the drainage network into your property.
Plastic pipe that has been chewed by rats.
Rats and Drains
We also find that rats often chew their way out through plastic pipework into homes or commercial properties, and they particularly love to chew through flexi-connectors that are often fitted on the rear of toilets these days. Rats will climb soil vent pipes in properties and will also climb rainwater downspouts too, and once at gutter level can usually find their way under roof tiles into lofts. Rats also burrow out of inspection chambers at or below ground level, where the cement benching has eroded.
In addition, drainage systems can degrade, or collapse over time, or can be damaged by building work or other works taking place, allowing sufficient sized gaps or holes for rats to exit, or to start chewing on to subsequently exit (rats constantly want to chew as their incisors continue to grow).
Where the external structure of your building appears sound at the time of our survey, and there are no other obvious access points, we may advise customers to arrange a CCTV survey of the drainage system serving their property. This is the only way to definitively identify any potential drainage defects which may be allowing rats into your property. We only suggest this where we believe the drainage system may be the cause of rat activity in your property, but where we do, it is very important that you choose a competent individual or company to complete the survey. We are often passed copies of CCTV survey reports which are only partial surveys, but do not always make this clear to the customer. In addition, we see surveys which do not set out all relevant information, or at worst, customers have received no written report at all, but are just given a verbal confirmation the drains are ‘ok’.
Mould growing on rat faeces in the clay drain pipe
Choosing The Right Contractor
We recommend customers ask questions of anyone they are considering using to undertake a drainage survey, to satisfy themselves that the company (and any employee completing the work) are competent and have sufficient knowledge and experience of inspecting drains specifically for defects that will allow rats to exit the system. Some companies specialise in this work and do not get involved in routine drainage work in respect of blockages etc. It is also important to ask whether the company are able to quote for, and undertake, any repairs they may identify as necessary. Any in-line repairs should always include stainless steel mesh, as rats can chew through fibreglass patch repairs. All repair work should come with a guarantee.
We recommend customers only use a drainage contractor who is a member of the National Association of Drainage Contractors (NADC). We also recommend customers only use a drain surveyor who has attended and passed the Certified Drain Surveyor course run by the NADC. The National Association of Drainage Contractors website can be found here: https://nadc.org.uk
Approved Document H of the Building Regulations covers drainage and also acknowledges the link between drains and rats in properties, and the risk of poor quality / sub-standard work on drainage systems. This document also sets out the requirements for all drainage work and alterations etc. This document can be found at: https://www.gov.uk/government/publications/drainage-and-waste-disposal-approved-document-h
Rats and Drains Preventative Measures
Notwithstanding any advice we may give regarding arranging a CCTV survey of the drainage system to your property, a couple of precautions that will always be recommended include the following:
- You may wish to consider drilling into all rainwater down pipes and inserting nails, screws or thick wire across the diameter of the pipe to prevent rats climbing but at the same time allowing water down. Alternatively a ball of chicken wire can be fitted at the top or bottom of all down pipes to prevent the risk of rodent climbing.
- Keep all toilet lids closed when not in use.
- If you have a disused toilet in an outbuilding or elsewhere, we recommend you cap this off; or as an absolute minimum, ensure there is always water in the bowl and the lid is kept closed.