Flooding

Blockages or problems with drainage are the responsibility of either the local utility company, Thames Water, or the owner of the property the drainage serves.

The division of responsibility depends on the location of the drain or sewer. This is explained in detail below the accompanying diagram, which shows how drains and sewers connect to different types of residential properties.

A drain is a single pipe serving one premises

A drain is an underground pipe, typically 4 inches in diameter, that carries surface or foul water from a single property. It usually discharges into a public sewer. The property owner is responsible for their drain up to the boundary of their property. Beyond this boundary, Thames Water, the sewerage undertaker, is responsible.

A sewer is a drain serving multiple premises

A sewer is an underground pipe that carries surface or foul water from more than one property. It may be located on private or public land. Thames Water is responsible for all sewers.

A lateral drain

This is a drain located outside the private boundary of the property it serves and may be on public land or neighbouring private land. Thames Water is responsible for lateral drains.

Road gullies and drains

These are responsible for collecting surface water from roads, not foul water from properties. The council handles blocked highway drains and road gullies that cause surface water flooding. Such issues should be reported using the online form provided below.

Report a drain or sewer problem

Blockages and defects

Drains and sewers, whether private or public, can become blocked for various reasons.

Common causes include:

• Build-up of fat in the pipe
• Foreign objects such as baby wipes, nappies, or sanitary products
• Poor design
• Tree roots
• Inadequate pipe fall or size
• Defective pipe sections or joints

If a blockage occurs in a drain serving a single property, only that property is affected. If a sewer is blocked, the first property impacted is typically the one immediately upstream, where sewage may overflow. All properties upstream will eventually be affected as waste water cannot flow away properly.

What should I do if I suspect a blockage (waste not flowing as usual)?

Speak to neighbours to determine which properties are affected.

If the blockage is solely in your drain, it is the responsibility of the property owner or landlord to resolve it. Arrange for a drainage specialist or contact your landlord or letting agent. Tenants may be responsible depending on their tenancy agreement and the cause of the blockage.

If multiple properties are affected, contact Thames Water, the statutory utility responsible for sewers, via their website.

Failure to address the issue can pose health risks. If owners do not act, the Local Authority may intervene, take formal action, and arrange for clearance. The costs, including an administrative fee, will be charged to those responsible.