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Last edited 17 Mar 2021
A lateral drain is a section of pipe that is positioned outside the boundary of a building. It may be located under a public pavement or road and either connects to a neighbour's drain or connects directly to a public sewer. It can also be placed under a property in situations where the sewer is shared between neighbours.
A lateral drain is a length of public drain that connects with the drains from other buildings to become a sewer. A public lateral drain carries wastewater and excrement away from a multi-occupant property such as a caravan site or a block of flats.
 Changes to maintenance arrangements
In England and Wales, the arrangement for lateral drains changed on 1 October 2011. Lateral drains that had been previously connected to the public sewer before 1 July 2011 were transferred to the ownership of the local sewerage companies (generally water companies). According to the regulation (referred to as The private sewers transfer regulations), ‘Lateral drains situated upstream of lengths of sewer which are on or under land opted-out of transfer by a Crown body, or which are owned by a railway undertaker (and therefore specifically excluded in the transfer regulations) are also transferred.’
If a private pipe becomes blocked before it joins the public infrastructure, it is the owner’s responsibility - not the sewerage authority - to pay for repairs or replacements of the pipe. It is generally not the responsibility of the building occupant or owner to maintain a lateral drain. Sewerage companies are typically responsible for public lateral drains since they are usually connected to a sewer network that is maintained by a local water company. This company is permitted to enter a property if it is necessary to inspect or service the public lateral drain.
 Adopting lateral drains
New or existing lateral drains can be adopted by a sewerage company under Section 102 of the Water Industry Act 1991 (for existing structures) or section 104 of the Water Industry Act 1991 (for new structures).
Those responsible for maintaining the lateral drain must agree to having this responsibility transferred to the sewerage company. Once an agreement has been reached, the sewerage company will then maintain the lateral drains at their own expense.
 Related articles on Designing Buildings Wiki
- Difference between drains and sewers
- Private sewer
- Sewer construction
- Waste water
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