--- title: "Tower Hamlets' Rat Problem and What It Means for Your Drains" canonical: "https://drainunblockerlondon.co.uk/blog/tower-hamlets-rat-problem-drains-london/" pubDate: 2026-05-26 author: John Hanson description: "Tower Hamlets consistently records London's highest rat call-out rates. The cause is not waste management alone — it is the borough's Victorian drain network. Here is what residents need to know." tags: [rats in drains, Tower Hamlets, London rat problem, Victorian drains, outdoor drain blockages] categories: [Drain Advice] --- Tower Hamlets records more rat infestations per square kilometre than any other London borough. The council receives thousands of rat-related complaints annually, and that figure has risen consistently over the past decade — a pattern echoed by the [2017 Whitechapel fatberg](https://www.bbc.co.uk/news/uk-england-london-41238272) discovery in the same East London sewer network. Pest controllers will tell you the cause is restaurant waste from Brick Lane and Bethnal Green, or the density of the housing stock. Both are factors. But the root cause — the one that makes the problem structurally worse year on year — is the state of the Victorian drain network running beneath almost every street in the borough. ## Why Tower Hamlets Has a Rat Problem Rats do not live in sewers by choice. They live where they find warmth, shelter, and food. A 19th-century combined sewer system — one that carries both sewage and surface rainwater — provides all three. The Victorian drains under Tower Hamlets are predominantly 100mm clay laterals feeding into larger brick egg-shaped sewers. Many of these drains are cracked, root-infiltrated, or have displaced joints that create gaps. A rat can squeeze through a gap of 20mm — roughly the diameter of a 50p coin. A cracked joint in a 100mm clay lateral creates an opening two or three times that size. Once inside the drain network, a rat has access to the entire connected system — from the sewer main under the road to the private lateral under your garden to, in the worst cases, the drain run beneath your floor slab. London's rat population has grown significantly since 2020. The combination of reduced pest control activity during the pandemic, increased organic waste in residential areas, and the accelerating deterioration of Victorian drainage infrastructure has created conditions where rat ingress through defective drains is no longer rare — it is a predictable consequence of deferred maintenance. ![Close-up of an old cast-iron drain grate set into damp paving stone with moss around the edge, overcast daylight, overhead angle](/images/blog/tower-hamlets-rat-problem-drains/old-cast-iron-drain-grate-moss-pavement.webp) ## The Drain Connection: How Rats Get In ### Fractured pipes A clay lateral pipe that has cracked under London Clay shrink-swell movement — common in the deep clay soils of inner East London — exposes the surrounding soil. Rats that are already living in the soil near the drain (attracted by the moisture and organic material seeping from a leaking joint) will exploit a crack to access the inside of the pipe system. ### Displaced joints Where sections of clay pipe have pulled apart at their joints — caused by soil settlement or root movement — the gap is large enough to allow rat entry. Displaced joints are one of the most common defects found on CCTV surveys of Tower Hamlets properties. The displacement creates not just a rat entry point but also a path for groundwater, tree roots, and debris to enter the pipe and accelerate blockage formation. ### Broken inspection chambers Above-ground inspection chambers — the brick or concrete boxes that provide access to drain runs in gardens and under paths — frequently crack with age. A broken chamber lid or crumbling chamber wall gives rats a surface-level entry point directly into the drain system without needing to work through the soil. ### Connections to the public sewer [Thames Water](https://www.thameswater.co.uk)'s main sewer network under Tower Hamlets is also ageing. Rats that access the public sewer from the street have a direct route into private laterals through any defective connection point. This is why properties can experience rat ingress in their drainage even when their own private pipes appear sound — the entry point may be in the adopted sewer upstream. ## What Rat Activity in Drains Looks Like If rats are using your drains as a travel route or nesting site, the signs are: - Scratching or scurrying sounds inside walls, particularly at night, on routes consistent with the drain run - Grease marks or droppings near drain access points, gullies, or inspection chambers - Gnaw marks on drain pipe insulation or around the base of the soil stack - A persistent drain smell that intensifies during cold weather (when rats descend deeper into the system) - Rats appearing in the garden near inspection chambers or drain gullies None of these signs alone proves rat ingress through the drain. But combined with any history of drain blockages or slow drainage, they are a strong indicator that the drain needs a CCTV inspection. ![Inside of a brick Victorian sewer tunnel, dimly lit with moisture glistening on the walls and a trickle of water in the invert channel, atmospheric, no people or animals](/images/blog/tower-hamlets-rat-problem-drains/victorian-sewer-tunnel-interior-brick-walls.webp) ## What to Do About It ### Step 1: CCTV survey the drain run A [CCTV drain survey](/services/cctv-drain-surveys/) in Tower Hamlets will typically reveal one or more of: fractured pipe, displaced joint, open rodding eye, or a broken inspection chamber that provides rat access. The survey footage is a forensic record — it shows exactly where the defect is, what type it is, and what repair is required. For [outdoor drain blockages](/services/blocked-drains/outdoor-drain-blockages/), a CCTV survey is the most cost-effective first step: it confirms whether the blockage has a structural cause (which will recur) or is a one-off accumulation (which may not). ### Step 2: Repair the defect Depending on what the survey finds: - **Cracked or displaced pipe sections**: pipe relining (CIPP) or, where the damage is severe, excavation and replacement. Relining is particularly suited to Tower Hamlets properties where the drain runs beneath a rear garden or under a shared path. - **Open joints**: re-lining seals open joints without excavation. Where movement is ongoing, an internal patch lining at the defect point may be the more durable solution. - **Broken inspection chambers**: chamber replacement or repair — either re-benching and re-topping with modern materials, or full chamber replacement. ### Step 3: Report to Thames Water if the defect is in adopted pipework If the CCTV survey shows the defect is in the section of drain adopted by Thames Water — the lateral outside your boundary or a main sewer — report it to Thames Water with the footage. Thames Water is obliged to repair defects in adopted pipework. Include the specific location from the CCTV report to support a faster response. For [blocked drains in Tower Hamlets](/locations/tower-hamlets/blocked-drains/) we prioritise urgent jobs for the fastest possible response. For neighbouring boroughs affected by the same Victorian drain network, see our pages for [Hackney](/locations/hackney/) and [Southwark](/locations/southwark/). ## Frequently Asked Questions ### Is a rat in my drain Thames Water's problem or mine? The rat problem in the drain network is a shared one. If the defect that allows rat access is in your private drain, it is your responsibility to repair it. If it is in the adopted public sewer, report it to Thames Water. A CCTV survey with a drainage plan will establish exactly where the entry point is and who is responsible for the repair. ### Can I seal my drain to stop rats getting in? You can fit rodent barriers — one-way valve devices installed in the drain that allow waste to pass out but physically prevent rats travelling upstream. These are a useful interim measure but not a substitute for repairing the underlying drain defect. A rat-exclusion valve installed into a cracked pipe will not last long. ### How common is rat ingress through drains in Tower Hamlets? Based on our callout data across the borough, rat ingress through drain defects accounts for a significant proportion of pest-related drainage investigations. Properties built before 1940 with no history of drain survey are the most at risk — particularly those with mature gardens where tree roots have had decades to exploit pipe joints. ### Will the pest controller deal with the drain issue? No. A pest controller can exterminate the rats currently on your property and proof entry points at ground level. They are not qualified to CCTV survey drain runs, identify structural defects, or carry out pipe relining. For a permanent solution, you need both services working together. ### How much does a CCTV drain survey cost in Tower Hamlets? The cost of a standard residential CCTV survey in Tower Hamlets depends on the number of drain runs and access available. Request a quote online via [our contact form](/contact/) for a fixed price before we attend.