Building and Developing

Sewer Adoption - New Site

Codes for adoption

From April 2020 Ofwat have introduced a standard practice across the Water Industry in England that all companies will follow regarding the adoption of newly constructed sewers. 

In October 2019, Ofwat approved the sewerage sector guidance documentation (SSG) to meet the requirements of the Code. From 1 April 2020 this guidance will come into force standardising process and procedure across the country.  As part of the SSG, ‘Sewers for Adoption’ has been replaced by the mandatory ‘Design & Construction Guidance (DCG) which gives provision for Sewerage Undertakers to adopt SUDs facilities.

Below is a helpful guide that sets out what you’ll need to do to offer new assets for adoption under the codes for adoption.

Step One

Pre-Planning Enquiry

This stage is designed to confirm the allowable rates of discharge to the point(s) on the existing network where a connection to a public sewer is required. Our team will also advise on any known capacity issues within the area and any diversions or requisitions that may be required.

You can apply for a developer enquiry using our developer enquiry application form.

Our Network Solutions team will look after your developer enquiry and if you have any queries, they can be contacted at

Following receipt of your developer enquiry response you may wish to talk to our Sewer Adoption Design Team about your sites strategy prior to completing a S104 submission. You can do this by simply completing our Pre-Design Strategic Discussion request application form

This stage helps with early engagement to capture the design of a site and enable the proposals for maintaining a sewerage system for its lifetime to be considered by the Sewerage Company. The earlier the discussions the better, being useful at any point before the S104 application is requested by the developer or recommended as part of the pre-planning enquiry.  It also allows the developer to confirm the future owner and maintainer of the sewerage system at the outset to use as part of their planning application.

Our Developer Services team can be contacted on 0800 707 6600 for further information. 

Step Two

Design of a new sewerage system

This stage is designed to confirm with the developer that the system conforms to the Codes of Adoption to enable a S104 Agreement to be entered into. It will confirm the technical acceptance of the design. It also allows the developer to determine the cost of the works at the outset of the development.

Sewers should be designed as per the Design & Construction Guidance (DCG) which is part of the Sewerage Sector Guidance (SSG)

To make an application for the adoption of a new sewerage system you will need to complete a S104 application. For help with your application please contact our Developer Services team on or 0800 707 6600.

If you are offering a pumping station for adoption, you will need to refer to the Severn Trent addendum on pumping stations.

Step Three

Adoption Agreements

When you have your technical approval in place for your S104, you will need to enter into a S104 agreement so we can formally adopt the sewers. As part of the SSG there is a Model Sewer Adoption Agreement available online. You can either prepare your own agreement using this template or ask us to produce one by providing the required documentation detailed in your technical compliance letter. 

No alterations to the Model Sewer Adoption Agreement will usually be permitted.

We appreciate that construction work may need to begin before the S104 agreement has been signed by all parties. So not to delay the start of your construction work, you can view and download an Early Start Request form (PDF) once you have received conditonal or technical acceptance and made payment of the S104 fees.

The early start request form can be submitted to we will then be in touch to arrange a pre-start meeting on site.

Step Four

Construction of sewerage system

Before construction work begins on new sewers proposed for adoption, a pre-start meeting must be completed. A Pre-Start Form (PDF) can be downloaded and submitted via

Once we’ve received this one of our Waste Construction Project Managers (WCPMs) will get in touch with to arrange a pre-start meeting.

During construction we’ll carry out inspections to ensure that the sewers are built as per the agreement. Our WCPMs will visit the site by appointment and also on a pro-active basis to ensure compliance with the agreement.

When a sites sewers are constructed and you reach 51% property occupancy, it becomes eligible to progress onto maintenance.

Step Five


When your sewers are ready to begin a maintenance period, please let us know by filling out a Pre-Maintenance Inspection form (PDF) and emailing it to us at

Before we can complete a maintenance inspection you’ll need to confirm/provide the following:

One of our WCPMs will then arrange to carry out a maintenance inspection to confirm that the works are suitable to enter a 12-month maintenance period.

Subsequently, we’ll issue the provisional certificate.

Step Six



When there are 3 months remaining on your maintenance period we’ll contact you to arrange a final inspection. Alternatively you can contact our team or your WCPM.

You will need to confirm that any necessary remedials have been completed and let us know of any operational issues than have occurred.

A final inspection can then be arranged and completed. When any outstanding remedials or legal issues are resolved we’ll happily issue the vesting certificate. 

You can also apply for this inspection using the Final Adoption Inspection Request form (PDF) if you’re not ready when we contact you. 

Step Seven


This stage is designed to confirm changes to the proposed design of a system for adoption once technical acceptance has been issued.

You’ll need to contact us regarding any variation to your design so we can assess if they are minor variations that can be accounted for on the as-built drawings or if a formal reassessment is required.

Please contact for further details.

Local Practices

As part of the overarching changes to the Water Industry Act 1991, that introduces statutory Codes for adoption agreements, water companies are requested to publish their proposals to implement local practices, i.e. where there is deviation from the standard practice.

The following are our current published local practices:


Whilst we aim to support you and deliver for you in a timely manner across the entire process we may occasionally fall short. If this is the case we shall email you regarding the nature and cause of the failure and set out our proposals to resolve. We’ll do this within one working day of the failure occurrence.

Should you believe our proposals to resolve are unacceptable you can request escalation to our compliance manager at who will respond within 5 working days of receipt.