Building over or near sewers

If you intend on constructing a building or extension over or near to a public sewer, certain constraints will apply. Public sewers are ‘drains’ serving more than one property that have either been adopted as public sewers or they were laid before 1st October 1937. Public sewers can be foul, surface water or combined.

Responsibility for the maintenance of public sewers in Essex and London rests with either Thames Water Utilities Plc or Anglian Water.

The Building Regulations require that development proposals are checked against the local water authority’s maps and consult them if any new building or extension is shown within 3 metres of a sewer shown on their map.

It is not possible to submit a Building Notice for a new building or extension within 3 metres of a sewer shown on the Thames Water or Anglian Water map of sewers. The law requires that a Full Plans application be submitted in all cases.

On 1st October 2011, water and sewage companies became responsible for shared private sewers, this means a build over agreement may be required if the drain is shared even if it does not appear on the mapping system.

For more information regarding public sewers you can visit:


CIOB LABCSmarter Planning ChampionPolicy Bee

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