Who Is Responsible for Drains in London? Owner vs Thames Water

In England, you are generally responsible for the drains that serve only your property and sit within your property boundary. Since 1 October 2011, most shared sewers and the lateral drains running outside your boundary to the public sewer have been the responsibility of the water and sewerage company, which in London is Thames Water. Where exactly the fault is decides who pays to fix it.

Drains, sewers and lateral drains

The terms matter, because responsibility follows them.

• A drain is a pipe that carries waste water away from one property.
• A lateral drain is the part of that pipe that lies outside the property boundary, on its way to the sewer, for example under the pavement or under a neighbour’s land.
• A sewer is a pipe that carries waste water from more than one property. It may run through gardens, under shared yards or under the road.

What changed in October 2011

Before 2011, homeowners were often responsible for shared private sewers and for the whole of their drain right up to the public sewer, even when it ran under the road. On 1 October 2011, most private sewers and lateral drains that connected to the public sewer network in England and Wales were transferred to the water and sewerage companies.

In practice, that means many pipes that used to be shared between neighbours, or that ran under a pavement, became Thames Water’s responsibility in London. Some pipes weren’t covered, for example drains that don’t connect to the public sewer, and arrangements for newer sewers can differ, so it’s worth checking with Thames Water if you’re unsure about a particular pipe.

What’s usually yours

• Waste pipes, traps and fittings inside the building.
• Gullies, inspection chambers and drain runs within your boundary that serve only your property.
• Rainwater pipes and soakaways serving only your property.

What’s usually the water company’s

• Public sewers, including those under roads.
• Shared sewers serving more than one property, even if they run through your garden.
• Your lateral drain, once it leaves your property boundary.

Flats, leaseholders and landlords

In a block of flats, the drains within the building and its grounds often serve several flats. Responsibility for those between the residents, the freeholder and any management company is normally set out in the lease. Typically a leaseholder looks after the pipes that serve only their flat, while shared stacks and drains are maintained by the freeholder and recharged through the service charge, but leases vary. Check yours, or ask your managing agent, before booking work.

If you rent, report drainage problems to your landlord or letting agent. Landlords usually have repairing obligations for drains and sanitation, but a blockage caused by misuse may be charged back to the tenant.

How to tell where the problem is

1. Check whether neighbours have the same problem. If several properties are affected, the blockage is likely in a shared sewer.
2. Lift your inspection chamber, if it is safe and light enough. If it is empty, the blockage is between your house and the chamber, which is usually your responsibility.
3. If your chamber is full, check the next chamber downstream if you can find it. A full chamber outside your boundary points to the lateral drain or sewer.
4. Look at the sewer records. Thames Water can provide a map of public sewers near your property, and your property search from purchase may include one.
5. Get the line surveyed if it is still unclear.

Using a CCTV survey to settle the question

When it isn’t clear who is responsible, a CCTV drain survey usually answers it. The camera records the drain from your chamber, and the footage shows the position of the fault measured from that point. Combined with the sewer records and the property boundary, that shows whether the defect is on your side or not.

That evidence is useful whichever way it goes. If the fault is yours, you know exactly what needs repairing. If it is in a shared sewer or lateral drain, you have footage to support your report to the water company.

Our drainage engineers cover Central London 24 hours a day, 7 days a week, with free quotations for unblocking, CCTV drain surveys and repairs. Call 020 3670 7648 and we’ll help you work out where the problem is.