Drainage systems are among the most overlooked entry points for rodents and other pests in London properties. From period townhouses in Kensington to commercial units in Central London, compromised pipework frequently provides concealed access directly into buildings.
So, are drain surveys for pests worth it?
From a professional pest control standpoint, particularly before purchasing or renovating a property, the answer is very often yes.
At Obsidian Environmental Services, our BPCA-accredited technicians combine over 65 years of practical field experience across London. We follow the British Pest Control Association’s best-practice guidance and adhere to recognised welfare standards, including those aligned with RSPCA principles, ensuring thatcontrol measures are lawful, humane, and effective.
This article explains when a drain camera survey is justified, what it uncovers, and how it can prevent substantial long-term costs.
Key Takeaways:
- Drain defects are a common hidden entry point for rats and mice.
- CCTV drain surveys provide non-invasive, precise diagnostics.
- Particularly valuable before property purchases or major renovations.
- Early identification prevents structural damage and recurring infestations.
- Enables targeted pest-proofing solutions, instead of guesswork.
Why Drains Are a Major Pest Entry Route in London Buildings
Rodents, particularly brown rats, are highly adapted to urban sewer systems. London’s ageing drainage infrastructure, combined with historic property conversions and basement developments, creates ideal access conditions.
Rats, and other rodents such as mice and even squirrels, due to their ever-growing, sharp teeth, can:
- Exploit cracked clay pipes
- Enter through displaced joints
- Gnaw through defective PVC/plastic pipework
- Travel through redundant connections
- Surface through broken interceptors or inspection chambers
Once inside a cavity wall, floor void, or service riser, they can move undetected between properties. Importantly, many infestations originate below ground level, meaning standard internal pest control alone may not resolve the root cause.
What Is a Drain Camera Survey?
A drain camera survey (CCTV drainage survey) is a non-invasive inspection method used to assess internal pipe condition. Our BPCA-certified and highly skilled technicians feed a high-resolution CCTV camera through your drainage system to identify:
- Cracks, fractures, or collapsed sections
- Displaced pipe joints
- Rodent entry points
- Root ingress
- Heavy scale buildup
- Blockages or debris accumulation
In many cases, we carry out high-pressure jetting beforehand to remove obstructions and improve visibility. Drain surveys are vital in offering a diagnostic approach that removes assumptions and replaces them with evidence-based pest control solutions.
Are Drain Surveys Worth It Before Buying a Property?
From a risk-management perspective: absolutely. Pre-purchase drain surveys are particularly important for:
- Period properties
- Properties with basement conversions
- Buildings with a history of rodent activity
- Properties undergoing renovation
- Multi-occupancy buildings
Undetected drainage defects can lead to:
- Recurring pest infestations
- Structural ground instability
- Collapsed drains requiring excavation
- Internal contamination
- Significant repair costs
Identifying issues early allows buyers or developers to negotiate repairs before completion or plan remedial works proactively.
Signs of a Pest Problem in Your Drains
From our 65+ years of experience, inspecting drains throughout London properties has been a major part of the job. From our historical findings, we have found that certain key indicators strongly suggest drainage-linked rodent activity:
- Unpleasant odours from sinks, showers, or toilets
- Scratching sounds within walls or beneath floors
- Rat or mouse sightings around the exterior
- Insects or drain flies are emerging indoors
- Gnaw marks on exposed pipework
- Damage around inspection covers
- Rats emerging through floor cracks near pipe routes
If these signs are present, a drain survey should be prioritised not only for reassurance, but for health and safety reasons.
What Happens If Drain Defects Are Found?
Drain-linked pest activity can present genuine public health risks. Rodents, cockroaches, and certain fly species are known mechanical carriers of harmful pathogens, capable of contaminating surfaces, food preparation areas, and stored goods through urine, droppings, regurgitation, and contact transfer.
Depending on findings, solutions may include:
- Detailed, transparent reports that identify present &/or potential issues
- Drain pit repair and remedial works around additional chamber installations
- Drain jetting for debris unblocking
- Installation of rodent prevention devices, such as one-way valves
Early investigation allows underlying access points to be identified and addressed before contamination risks escalate, especially around children, vulnerable individuals and commercial environments where hygiene is critical.
Why DIY Drain Inspections are Not Enough
Attempting to inspect drains without specialist equipment frequently results in misdiagnosis. Surface-level checks may identify a blockage or visible damage, but they rarely reveal the underlying structural fault that allows pests to enter in the first place.
Drain-related infestations are rarely resolved with internal trapping alone. Without identifying and addressing the below-ground access point/’s, the root cause remains active.
- Rodents may continue entering the system.
- Multiple properties may remain connected to the same breach.
- Control becomes reactive rather than preventative.
Professional CCTV surveys provide certainty. This is particularly critical in London buildings, where shared drainage systems are common.
Cutting-Edge Pest Detection Technology
At Obsidian Environmental Services, our approach integrates:
- Specialist CCTV drain inspection equipment
- High-pressure jetting systems
- Structural drainage repair capability
- Rodent-proofing installation expertise
With over 65 years of combined experience across London, we understand how drainage failures intersect with pest behaviour and know how to implement rapid prevention strategies when and where required.
Are Drain Surveys for Pests Worth It?
If you are dealing with unexplained rodent activity, buying a property, or investing in renovation works, a drain survey is often one of the most financially prudent steps you can take. It gives clarity and peace of mind by utilising pest control techniques for structural integrity.
For London property owners where drainage infrastructure is complex and interconnected, this diagnostic clarity is invaluable.
Protect Your Property with a Professional Drain Camera Survey
If you suspect rodents may be accessing your property via the drainage system, or you want reassurance before purchase or renovation, professional inspection is the safest approach.
Obsidian Environmental Services provides expert CCTV drain surveys across London, combining pest control expertise with structural drainage diagnostics.
Learn more about our Drain Camera Surveys or arrange a professional inspection today.
Call us on 020 8050 0238 or book your survey online to safeguard your property from hidden drainage-related pest risks.
Further Reading
British Pest Control Association – Guidance on Rodent Control
