Down the drain: blocked pipes, slow drains, and what landlords need to know

Blocked drains are, unglamorously, one of the most common maintenance calls in rental properties. They're rarely dramatic — no flooding, no emergency, just a sink that empties slowly or a shower that pools. But left unattended, a partial blockage becomes a full one, and a slow drain that was a five-minute fix can become a job that involves clearing out under the kitchen sink and explaining to a tenant why they can't use the bathroom.

Here's what landlords need to know.

Who's responsible for a blocked drain?

This is where it gets nuanced. As a landlord, you're responsible under Section 11 of the Landlord and Tenant Act 1985 for keeping drains and drainage pipes in repair and proper working order. But that responsibility sits alongside the tenant's obligation not to misuse the property — and the most common cause of blocked drains in rental properties is misuse: wipes (even "flushable" ones), sanitary products, cooking fat, and food debris going where they shouldn't.

In practice, if a drain was clear when the tenancy started and has become blocked through use, the question of whether it's fair wear and tear or tenant-caused damage depends on what caused the blockage. A root ingress or collapsed pipe section is a landlord repair. A drain full of wet wipes is not. The distinction matters at end of tenancy and it matters for who bears the cost.

Kitchen sinks

The most common kitchen drain issue is a build-up of grease, fat, and food debris in the trap or the short run of pipe below it. It develops slowly and announces itself as a gradually slower drain before it stops entirely. A strainer over the plughole is the simplest prevention. Once blocked, the trap under the sink usually unscrew by hand and can be cleared — but if the blockage is further along the pipe, it needs a drain rod or a proper flush.

If you're finding the same sink blocks repeatedly between tenancies or during a long one, it's worth checking whether the pipework gradient is correct. A drain that sits too flat doesn't self-clear the way it should.

Bathrooms

Bathroom blockages are almost always hair — in the shower trap, the bath trap, or the basin overflow. Again, a strainer or hair catcher solves the problem entirely and is worth putting in before a tenancy starts. The alternative is a tenant calling three months in about a shower that's not draining, and a job that's mildly unpleasant for whoever clears it.

Toilets are a separate category. The rule for what goes in a toilet is simple — waste and toilet paper — and anything else is a foreseeable cause of blockage. A note in the property handbook about this is not excessive. It's the kind of thing that genuinely reduces calls.

External drains and gullies

External drainage — the gullies that take water from downpipes and surface drainage — is often ignored until it fails. Leaves, debris, and silt accumulate over time and the gully blocks, leading to water backing up or pooling around the base of the building. An annual clear of external gullies is a small job and worth building into regular maintenance, particularly in autumn.

If an external drain is repeatedly blocking despite being cleared, it's worth putting a camera down it. Root ingress and partial collapses are common in London's older drainage systems and neither gets better on its own.

Prevention is genuinely easier than cure

The landlords who have the fewest drain calls are the ones who start a tenancy with clear drains, a strainer in every plughole, and a brief word in the property handbook about what doesn't go down the toilet. None of this is complicated, and it removes a category of maintenance call almost entirely.

If you've got a drain issue — or want a general inspection of drainage as part of a pre-tenancy visit — give us a call on 020 7993 8277 or email info@lapps.co.uk.

Legal disclaimer: The information in this post is provided for general guidance purposes only and does not constitute legal advice. Landlord and tenant responsibilities can vary depending on the specific circumstances and tenancy agreement — we recommend seeking professional advice if you are uncertain about liability for any repair. LAP Property Services accepts no liability for any decisions made in reliance on this content.

LAP Property Services provide property maintenance, electrical, gas, and compliance services to landlords and letting agents across London. Visit www.lapps.co.uk to find out more.