Adopting existing sewerage systems


Do you have a private sewerage system that you’d like us to consider adopting into our network? Once it’s adopted, we will be responsible for its maintenance.

While the majority of private sewers and lateral drains became adopted by us in 2011, there were some that didn’t transfer to our ownership. We have a duty to adopt private sewers when everyone who is served by those sewers wants us to.

However, we can only adopt sewers and lateral drains which meet a certain standard. Any work that needs to be carried out to get your sewerage system to that standard is your responsibility.

Take a read of our guidance notes to find out more and for guidance on how to fill in the application form.

How much will it cost?

For the charges of this service, please take a look at our schedule of charges.

Regulation to be aware of

  • Most private sewers must be adopted by us, apart from some cases.
  • If you want to build a lateral drain to connect to a public sewer which is located outside your new property boundary, you must always apply for an adoption agreement with us before any work begins.
  • For the adoption of proposed sewerage, you must enter into the adoption agreement before beginning building, in line with the Water Industry Act 1991. If you don’t have an adoption agreement in place, then you won’t be allowed to connect to the public sewer.
  • Sewers must comply with the mandatory standard set out in The Welsh Ministers Standards for Gravity Foul Sewers and Lateral Drains.
  • Adoptable surface water sewers and lateral drains should comply with the standards set out within the Design Guide ‘Sewers for Adoption 7th Edition'.