Public sewer
![]() |
The Thames tideway tunnel comprises a 24km long 7.2m diameter sewer running from Acton in the west to Abbey Mills in the east. It will have a holding storage capacity of 1.6 million cubic metres. |
A pipe that serves only one property is referred to as a drain. Drains are privately owned and maintained as far as the boundary of the property. Beyond the boundary of the property a drain is referred to as a public lateral drain.
A pipe that serves more than one property is referred to as a sewer. Sewers that connect to the public sewer network are referred to as public sewers.
The sewer system, that is, the underground network of pipes that carries sewage (waste water and excrement), other waste water and surface water run-off, from properties to treatment facilities or other disposal points is referred to as sewerage.
Under the Public Health Act 1936 all sewers (as defined by the Public Health Act 1875) which were in existence on 1 October 1937 became public sewers. After 1937 new sewers were only public if they were laid or adopted by the sewerage undertaker.
However, on 1 October 2011 in England and Wales, private sewers and lateral drains that were connected to the public sewer before 1 July 2011 were transferred to the ownership of the regulated sewerage companies (generally water companies).
It is possible to apply for new or existing sewers or lateral drains to be adopted by a sewerage company. For more information see:
Public sewers usually run under roads or public open spaces, but they may also run through private property such as gardens. The sewerage company has a right of access to these public sewers in order to maintain them.
Permission is required from the sewerage company to build over a public sewer. Failure to obtain permission may result in the withholding of a building regulations completion certificate.
It is also possible to have public sewers diverted under Section 185 of the Water Industry Act.
The route of existing mapped public sewers can be determined by inspecting local authority records or by contacting the local sewerage company. There may also be details in property deeds. However, many public sewers are not mapped. In this case, it may be necessary to carry out inspections from manholes, to undertake an electronic sewer trace or to dig trial holes.
- A surface water drain or sewer is a pipe that carries only surface water, not foul water.
- A foul water drain or sewer is a pipe that carries waste water from a property such as from a toilet, bath, washing machine and so on. Surface water should not discharge into a foul water drain or sewer, as this can cause flooding of foul water.
- A rising main is a pressurised sewer that can be used to pump foul or surface water.
[edit] Related articles on Designing Buildings
- Cesspool.
- Clarified water.
- Difference between drains and sewers.
- Drainage.
- Drains.
- Grease management.
- Manhole.
- Private sewer.
- Public Health Act 1875.
- Safe working in drains and sewers.
- Sanitary pipework.
- Section 102 existing sewer adoption.
- Section 104 new sewer adoption.
- Septic tank.
- Sewer construction.
- Sewerage.
- Sewerage company.
- Sustainable urban drainage systems SUDS.
- Thames Tideway Tunnel.
- The redevelopment of Leicester's sewerage system by Joseph Gordon.
- Waste water.
Featured articles and news
OpenUSD possibilities: Look before you leap
Being ready for the OpenUSD solutions set to transform architecture and design.
Global Asbestos Awareness Week 2025
Highlighting the continuing threat to trades persons.
Retrofit of Buildings, a CIOB Technical Publication
Now available in Arabic and Chinese aswell as English.
The context, schemes, standards, roles and relevance of the Building Safety Act.
Retrofit 25 – What's Stopping Us?
Exhibition Opens at The Building Centre.
Types of work to existing buildings
A simple circular economy wiki breakdown with further links.
A threat to the creativity that makes London special.
How can digital twins boost profitability within construction?
The smart construction dashboard, as-built data and site changes forming an accurate digital twin.
Unlocking surplus public defence land and more to speed up the delivery of housing.
The Planning and Infrastructure Bill
An outline of the bill with a mix of reactions on potential impacts from IHBC, CIEEM, CIC, ACE and EIC.
Farnborough College Unveils its Half-house for Sustainable Construction Training.
Spring Statement 2025 with reactions from industry
Confirming previously announced funding, and welfare changes amid adjusted growth forecast.
Scottish Government responds to Grenfell report
As fund for unsafe cladding assessments is launched.
CLC and BSR process map for HRB approvals
One of the initial outputs of their weekly BSR meetings.
Building Safety Levy technical consultation response
Details of the planned levy now due in 2026.
Great British Energy install solar on school and NHS sites
200 schools and 200 NHS sites to get solar systems, as first project of the newly formed government initiative.
600 million for 60,000 more skilled construction workers
Announced by Treasury ahead of the Spring Statement.