Answer: The law regarding Private Sewers changed on 1st October 2011. Since that date, private sewers and private lateral drains outside the boundary of a property became adopted and within the ownership of the six Water Companies as did any shared drains within private property. It is usual for lengths of private sewer to be connected from the property to the mains. When these lengths of private sewer connect only the property to the mains, the expense of repair of this drain or sewer will fall entirely on the owner until it leaves the boundary of the property where it will become a public sewer/drain. If there is a length of private sewer or drain used jointly with neighbouring properties, the sewer or drain will become a public sewer or drain as soon as it leaves the boundary of the first property connected to it. Under the previous system, many property owners had legal obligations (usually jointly with adjoining owners) for the upkeep of sewers and pipework beyond their property boundaries up to the connection with the main public sewer. Since the transfer of ownership on 1st October 2011, the responsibility for maintenance and repair of these drains and sewers is now on the Water Companies. The sewers/drains which were previously in private ownership have not been mapped as it was deemed to be too costly to implement. There are now many more public sewers/drains within a property boundary and the Water Authority will require a Build Over Agreement and compliance with building regulations if any extension is to be built within three metres of a public sewer.
ConstructAid can advise on your particular case. We have also included an article on our Blog Section (follow link) of the website with links to Thames Water and Anglian Water to their guidance notes on Build Over Agreements and a guide to their fees. Please Contact Us (follow link) if you wish to discuss these issues further.