Rats in Drains: Causes, Signs & How to Stop Them

Nobody wants to share their home with rats. But if you've been hearing scratching under the floorboards, finding droppings in the kitchen, or catching a whiff of something unpleasant near your drains, there's a good chance that's exactly what's happening — and the rats are almost certainly coming from underground.

Why Rats Live in Drains

• Warmth — Underground pipes stay at a relatively constant temperature year-round.
• Food — Food waste flushed down sinks and toilets provides a steady supply.
• Water — There's always water flowing through sewers.
• Shelter — Underground pipes protect rats from predators and the elements.

Signs of Rats in Your Drains

• Scratching or scurrying noises — particularly at night, under floorboards or behind walls.
• Droppings near manholes — dark, pellet-shaped, about 10–15mm long.
• Gnaw marks on pipes — rats gnaw constantly; plastic waste pipes are vulnerable.
• Unpleasant smells — a persistent musky smell near drain fittings.
• Displaced manhole covers or damaged fittings — rats squeeze through surprisingly small gaps.
• Toilet disturbances — rats can swim up through the toilet from the drain.

Many of these signs overlap with signs of a blocked drain — a damaged drain makes rat access even easier.

How Rats Get from the Drain into Your Home

• Broken or displaced drain pipes — rats squeeze through gaps into the surrounding soil.
• Missing inspection chamber covers — direct access to the surface.
• Damaged soil vent pipes — cracks or gaps at the base are entry points.
• Failed toilet pan connectors — the flexible connector deteriorates over time.

Why Pest Control Alone Doesn't Work

If rats are entering through the drains, poison and traps only treat the symptom, not the cause. The drain network has a virtually unlimited supply of rats, and as long as there's an entry point, they'll keep coming. It's like bailing water out of a boat without fixing the hole.

The only permanent solution is to find and seal the entry points — and that starts with a CCTV drain survey.

CCTV Surveys: Finding the Entry Points

A CCTV drain survey inspects every joint, connection, and fitting, looking for cracked pipes, displaced joints, missing access points, and evidence of rat activity.

For a real-world example, see our rat ingress survey case study from Leeds, where we traced a rat problem back to its source and sealed the entry points.

Drain Proofing Solutions

Non-Return Valves (Rat Blockers)

One-way valves fitted inside the drain pipe. They allow sewage to flow out but prevent rats from travelling back up towards your property.

Pipe Repairs

Cracked, broken, or displaced pipes need repairing — often using no-dig methods. See our guide on drain repair costs.

Sealing Access Points

Open rodding eyes, gaps around pipe connections, and damaged inspection chamber covers all need sealing.

Interceptor Traps

Older properties often have an interceptor trap with a missing stopper, creating a direct route from the public sewer. Replacing the stopper or fitting a rat flap can solve the problem immediately.

The Right Approach

• Step 1 — Pest control to deal with rats already inside
• Step 2 — CCTV drain survey to find entry points
• Step 3 — Drain repairs and rat proofing to seal entry points permanently

Get Your Drains Surveyed

Call UK Drainage Services on 0333 577 4242 and book a CCTV drain survey. We'll find the entry points, recommend the right solution, and carry out the drain proofing to stop the problem for good.