Who is responsible for a blocked drain in England?

The short version

Pipework inside your boundary, serving only your property, is yours to maintain and repair.

Pipework that serves more than one property, or that runs beyond your boundary towards the public sewer, generally transferred to the water company in October 2011. For nearly every London address that means Thames Water, and they attend faults on their pipework at no cost to you.

That transfer is why so many people are still paying for repairs that are not theirs: the rule changed, and nobody sent a letter explaining it.

Where the line actually falls

The practical test is two questions. Does this pipe serve anyone else? Is the fault before or after my boundary?

A drain serving one house, within the garden, is a private drain. Once it crosses the boundary towards the sewer it is generally a lateral drain and the water company’s. Once it takes flow from more than one property it is generally a sewer, and theirs too.

This is why locating a fault matters as much as clearing it, and why we open chambers along the run rather than clearing the first one we reach.

Terraced streets, where it matters most

Victorian terraces frequently share a run at the front or rear before it reaches the sewer. That shared section is very often not yours, even though it passes through your garden.

So a blockage affecting your kitchen may sit on pipework the water company maintains. Report it to them first: they will attend and, if it is theirs, clear it without charging you. We cover the pattern in drainage in Victorian terraces.

Flats and blocks

Different rules again, set by the lease rather than by statute. Broadly, pipework serving only your flat is yours; the shared stack and building drainage are the freeholder’s, funded through the service charge.

Read the lease before accepting an invoice. More in converted flats and shared stacks and mansion blocks.

Rented property

The landlord is responsible for keeping drains, sinks, baths and sanitary fittings in repair under section 11 of the Landlord and Tenant Act 1985, and that cannot be contracted out of in a standard tenancy.

A blockage caused by tenant misuse, such as wipes or cooking fat, can reasonably fall to the tenant. A collapsed clay drain cannot. See landlord obligations.

What to do before paying anyone

1. Establish whether other properties are affected. If neighbours have the same problem, it is almost certainly a shared run.
2. Report it to Thames Water first if there is any chance it is theirs. It costs nothing to ask.
3. If you do engage a contractor, ask them to locate the fault and tell you which side of the boundary it sits on.
4. Get that in writing. It is what you need if there is any argument later.

We do this as standard, including on the occasions when the honest answer is that you should not be paying us. See what our work costs.

Local pages with call-out times and prices for the area: CCTV drain surveys in Lambeth, CCTV drain surveys in Southwark and French drains in Southwark.