Skip to main content

Sewers and drains

Our Environmental Health team ensures that private drainage systems operate efficiently.

The responsibility for unblocking or repairing of problem sections of foul sewage systems will depend upon whether a sewer is public or private.  Drains connected to septic tanks or cess pits will remain the responsibility of those who own or use them. 

Sewers and drains maintained by Thames Water

Main public sewers, private sewers and lateral drains are maintained by Thames Water

Private drains

Private drains are the responsibility of those who use them.

Find out more about Maintaining secure water supplies, high standards of drinking water and effective sewerage services on

Is your sewer public or private?

  • The underground waste pipe that exits your house is called a drain. The householder is responsible for the maintenance of that drain until it connects with a sewer.
  • If this drain then joins a drain from another property, the pipe becomes a private sewer from that joint onwards.
  • In the case where a blockage or defect occurs on the private sewer before reaching the public sewer, it is the water company (eg Thames Water) that is responsible.
  • The boundary of the property does not indicate the end of responsibility. This extends up to and includes the connection with the public sewerage system.
  • Where a householder's drain has crossed the boundary to another property or land, but has not yet joined another drain (thus becoming a sewer), it is known as a lateral drain. Thames Water will usually deal with issues arising on lateral drains.
  • Find out more about maintaining secure water supplies, high standards of drinking water and effective sewerage on Water and sewerage services on
  • Sewers built before 1 October 1937 are known as 'Section 24 sewers'. They fit the general description of private sewers but they are actually public and therefore managed by the local sewerage company.

What to do if your sewer or drain is blocked

If you are on a mains drainage system, please contact Thames Water in the first instance.  If you are using a cesspit or septic tank, or if you know the drain is your responsibility, contact a private drain cleaning company.

If Thames Water are unable to help, environmental health officers will determine the extent of the problem, the number of properties involved, the action required to resolve the problem, and who is responsible.  Please contact us:


Tel: 01483 523393

Formal action to clear or repair a drain

Clearing a drain or private sewer

If it is your responsibility to clear your drain and the water company's responsibility to deal with private sewers, we can issue a Statutory Notice if anyone fails to do so. Those receiving a Notice would be required to remove obstructions within 48 hours. If the notice is not complied with, we can complete the work. The cost for the works, plus any administrative fees, will be charged to those responsible.

Repairing a damaged drain or private sewer

A Building Act 1984, Section 59 Notice would require the people responsible to repair damaged parts of a private sewer. The notice or covering letter will indicate all other parties involved. If the notice is not complied with, we will complete the work and the cost, plus any administrative fees, will be charged.

Problems relating to both public and private sewers are dealt with by Thames Water, the company responsible for maintaining the sewers in Waverley. A notice may be served on them if necessary.