Blocked drains

When drains and sewers become blocked or broken there is often confusion about who has the responsibility to sort out the problem. This section advises householders who to contact if they are affected by a broken pipe or a blockage. Dependent on the circumstances, some of all of the following people may be liable for the cost of remedying any blockages or defects.

  • Individual Homeowners
  • Thames Water Utilities Ltd
  • The Landlord
  • The Property Freeholder
  • Occupiers

Drainage law applies to both foul and surface water pipes. The term foul waste does not just mean the waste from the toilet but also includes the waste from kitchen sinks, basins, baths, showers, dishwashers and washing machines etc.

Responsibility for drains and sewers

Go to Thames Water Website for more information.

Private drain

Where a property was already connected to a public sewer on 1 July 2011, the property owner is responsible for the maintenance of that part of the pipe or pipes which solely serve their property and are on their own land; this is called a private drain. (N.B. Leaseholders are likely to be responsible to their freeholder to make contributions for such maintenance).

Pipes serving a single property which do not ultimately connect to a public sewer but which end up in a treatment plant or soak away for example are also considered to be private drains. This is still the case even if these pipes go outside the curtilage of the building.

Responsibility for a private drain

Blockage - where blockages occur in a private drain then it is normally considered to be the responsibility of the occupier to unblock it. This might be the owner or a tenant. If the blockage however has been caused by a defect then see below.

Defective - where a private drain is found to be structurally defective then it is the responsibility of the freeholder or homeowner to remove any resulting blockages and to repair or replace it.

Lateral drain

Pipes which serve the property, (and which ultimately connect to a public sewer), but which are under public land (the highway, footpaths, verges) or private land are called lateral drains.

Responsibility for a lateral drain

Lateral Drains are the responsibility of Thames Water. In some cases it will be difficult to determine where a blockage is. i.e. in a private or a lateral drain. Investigation may need to be carried out by the householder or Thames Water to determine which party is responsible in each particular case. Thames Water can be telephoned on 08459 200 800 (local rate call) about blockages, and will clear their lateral drains free of charge.

Public sewer

These are the pipes which serve multiple properties and which were either laid by or have been adopted by Thames Water.

Responsibility for a public sewer

The responsibility for clearance and maintenance of public sewers rests with Thames Water in this area. The Council has a copy of the public sewer map, which has been supplied to us by Thames Water. This can be viewed by anyone upon visiting the Town Hall in Reigate, but an appointment must be arranged first, via Environmental Health.

Private sewer

Where the drains of multiple properties converge and become shared but do not ultimately connect to a public sewer then these are private sewers.

Responsibility for private sewers

The responsibility for the clearance of private sewers rests with the occupiers upstream of the blockage. The responsibility for maintenance of private sewers rests with the property owners upstream of the defect. If the waste from your house flows though a private sewer then you are partly responsible for it. (As are all the other households sharing this pipe).

The joint responsibilities for clearance and maintenance described above apply from the point at which the pipe becomes shared with another households, downstream to the end point which might be; a river, a soak away or a treatment plant. This end point can be at some distance from the houses and is usually beyond their gardens.


Curtilage - has not been defined for the purpose of these responsibilities. However the dictionary definition of curtilage is" the area of land occupied by a dwelling, its land and outbuildings". The curtilage of a property is broadly similar to a freehold boundary, although further guidance may be issued in due course.

Drain - a drain is a pipe that takes foul or surface water waste from a single property or from properties within the same curtilage.

Lateral Drain - a lateral drain is the part of your private drain that lies outside your property boundary/curtilage under public land (the highway, footpaths, verges) or private land.

Private Sewer - a private sewer is a pipe that takes the foul or surface water waste from mor than one property in different curtilages, but that does not discharge into a public sewer.

Public Sewer - a public sewer is a pipe that carries foul or surface water waste from more than one property and that has been laid or adopted by Thames Water (in this area)