Self-lay schemes

New water mains for your development can be laid by us or you can use your own contractor, known as a self-lay provider (SLP). Once your development is complete, we’ll adopt the water network as long as it meets the guidance we provide below.

Finding a self-lay provider

To make sure all work is carried out to national industry standards, self-lay providers must be accredited to the Water Industry Registration Scheme (WIRS), run by Lloyd's Register.

You can find a WIRS accredited self-lay provider, along with information about the scheme, on the Lloyd's Register website.


Codes for adoption

In January 2021, Ofwat introduced a standard practice across the water industry in England for water companies to follow when adopting self-laid mains.

This standard practice is known as the water code for adoption and is also referred to as ‘the codes’. You can find out more about the codes here on the Water UK website.


Design and construction specification

Any work completed by a self-lay provider will need to meet the requirements of our Design and Construction Specification (DCS) Document, which is based on the template provided under the codes.

View the Design and Construction Specification (DCS) Document

The guide below explains how to work with self-lay providers, including links to relevant application forms. You can find out how much we charge for these applications in our New Connections Charging document.

If you’re a self-lay provider looking to complete a development in our network, here are the steps to help you with your project.


Steps to help you with your project

Don't worry, we’ll be in touch along the way to make sure everything goes smoothly.

  1. You apply to 'Lay a new main' on Get Connected

    Fill out all the details and pay. We'll review your enquiry within 5 days.

  2. We'll respond with a Point of Connection report

    We'll send your report to your Get Connected dashboard within 14 days, or 28 days if your site is complex.

  3. You confirm the Point of Connection via Get Connected

    You submit your mains design, or confirm your request for us to design, and pay the relevant fee.

  4. We accept your design

    We’ll assess your design and will respond to you within 14 days. Along with your design acceptance, we’ll send you a form which you need to sign before we can progress.

  5. You pay non-contestable costs

    You’ll also need to pay non-contestable costs.

  6. You sign the adoption agreement

    An adoption agreement will need to be signed by all parties.

  7. You construct the new main

    We'll arrange a pre-start meeting to go through next steps and the documents required at each stage. During construction, you'll need to upload a weekly 'whereabouts form' to notify us of work on site.

  8. You apply for Service Connections

    Using your Get Connected login, tell us how you want to make service connections and what meters you require.

  9. We will send your declaration of vesting once everything is complete on site 

    Once we have reviewed the documents we'll send your certificate via Get Connected.

Stage 1 – Pre-planning enquiry (developer)

Engaging us before you apply for planning permission allows us to plan for future network capacity requirements and help you make an informed choice on the delivery route for the water infrastructure to the site (i.e. water company requisition, self-lay, new appointment or variation (NAV)).

Please submit your completed Water Pre-planning Enquiry Application Form to [email protected].

View the Water Pre-planning Enquiry Application Form

We’ll review the application within seven calendar days of receipt and you’ll receive a pre-planning enquiry report within 21 calendar days.

Stage 2 – Point of connection application (SLP)

A point of connection application allows us to confirm the point(s) where a self-laid main can be connected to an existing main on our network so you can estimate costs, determine the scope of the self-lay works and produce a design.

Log into your Get Connected account and tell us you want to Lay a new main.

We’ll review your application within five calendar days of receipt and you’ll receive a point of connection report within 10 calendar days – unless your site is complex, in which case this timescale will increase to 28 calendar days.

A complex site is one where any of the following apply:

  • Number of plots on site over 500
  • Special engineering difficulties identified
  • Mains pressure (where the site is higher than the reservoir on a gravity-fed system)
  • Reinforcement that may require more than laying or upsizing a main (e.g. booster pump)
  • Highways constraints (e.g. major trunk road/motorways where a site meeting with a highway authority is specifically required)
  • Environmental issues in respect of SSSI or other designated sites
  • Site of archaeological interest
  • Third party and Crown Estate land
  • Protected undertakers (e.g. other utilities and Network Rail)
  • Schedule 13 Water Industry Act 1991 constraints

You can also work out the approximate costs for the work using our connection charging calculator.

Stage 3 – Design acceptance / S41 to S51 conversion applications (SLP)

Please tell us when you apply to Lay a new main whether you intend to design the main yourself or wish for us to design a main for you to lay from your agreed Point of Connection. The costs for each service can be found in our New Connection Charging Arrangements. All designs for contestable work will need to take account of the contestable summary table in 9.3 of our Design and Construction Specification (DCS) Document. We will design the non-contestable work and provide you with the costs for delivery. Both parties will need to sign an agreement to work to the agreed designs.

Get Connected login

Download the Design and Construction Specification (DCS) Document

For S41 to S51 conversion applications, please use the S41 to S51 Conversion application form. Please note this is for the conversion of issued S41 designs and cannot be used to change an S41 issued design. If the S41 design needs amending, please follow the S51 Design acceptance application route, by submitting your own SLP design. If the S41 design was issued less than 12 months ago, the same Point of Connection (POC) identified can be used. If not, a new POC application is required to re-validate the POC used in the original issued S41.

Download the S41 to S51 Conversion application form

The application fee is £649.20 (incl. VAT) and any subsequent re-design checks/approval fees will be £256.80 (incl. VAT).

It is mandatory to have an identified point of connection for your design so please ensure that you have procured this via our point of connection application (Stage 2) prior to submitting your design to us. This point of connection will need to be indicated on your design to allow us to design the non-contestable work.

You’ll also need to complete the following two forms with your application:

Download the Contaminated land assessment site history questionnaire

Download the Contaminated land – assessment guidance

These forms are a risk assessment for the water pipes and you'll need to ensure they're signed-off by a suitable qualified person.

We'll ask you to complete the forms above at this stage and attach them to your application on Get Connected.
We'll also need to see the following, which can also be uploaded to the Get Connected portal:
  • Most recent site layout in CAD format
  • Easement drawing (CAD and PDF) (if applicable)
  • Proposed water network design (CAD and PDF format)
  • Confirmation of the lead designer for the development and a copy of HSE F10 form (if applicable)
  • Main contractor’s project health and safety plan
  • Pre-remediation or post-remediation site investigation (SI) report (where applicable)
  • List of affected land owners (if applicable)
  • The estimated date the permanent water supply is required

To support the Southern Water DCS, we've also created a Mains Design Considerations Document, which provides guidance on things to consider when designing your water main. These considerations are informed by our experience in designing water mains and the associated maintenance requirements for the asset.

Download the Mains Design Considerations Document

We've also included features that should be considered on the Computer Aided Design (CAD). We hope you find what we've set out in the Document informative and that it will help you produce a suitable design.

If the water main is to be laid across third party land, please ensure you're familiar with the guidance for preparing plans for Land Registry.

Once we have assessed your design and all the necessary information has been provided to us, we’ll respond to you within 14 calendar days confirming design acceptance. This acceptance will be provided if the deign meets the design requirements set out in our DCS document.

If the design is for a development that meets the criteria for a complex site (as set out in Stage 2), we may need to increase our response time to 21 calendar days. However, we’ll let you know within 14 calendar if this is the case.

Stage 4 – Signing the Adoption Agreement (all parties)

Along with your design acceptance, we’ll send you a Design Acceptance Form, please fill out and sign the Design Acceptance Form 'and return via your Get Connected login., this confirms we’ve reached an agreement on the design and can proceed with the Adoption Agreement.

When returning the design acceptance form, please include any non-contestable costs / outstanding payments due. We expect all non-contestable costs to be paid before we enter into an Adoption Agreement as this payment allows us to progress the associated work and meet the agreed source of water connection date. Your source of water connection will need to be made by us as this is non-contestable work for your site.

Once the design has been agreed there are two options for progressing an adoption agreement with us:

We provide a draft Adoption Agreement to you

You can send an email to [email protected] requesting an Adoption Agreement template from us, providing us with sufficient information for us to complete WAA Schedules 1 and 3, such that it reflects the preferred allocation of responsibility for Contestable Work and Services. Also include a proposed source of water delivery date.

We will come back to you within seven calendar days of receiving your request, either confirming the source of water delivery date and providing you with a draft Adoption Agreement or proposing an alternative date for your consideration, with our rationale as to why we are proposing a different date.

Once we have confirmed a source of water delivery date with you, please ensure the Adoption Agreement is signed by all parties and sent back to us at [email protected], we will then sign it and provide you with a copy.

You send us a draft Adoption Agreement

You can send us a draft water Adoption Agreement to [email protected], (as an example, here's Water UK's agreement template). Within the agreement you will need to allocate responsibility for those parts of the activities which are carried out by each of the developer, SLP and ourselves and include this information in Schedule 1 (Connection Specification) and Schedule 3 (Company Works). Also include a proposed source of water delivery date.

We will review the agreement and come back to you either confirming the source of water delivery date or proposing an alternative source of water date for your consideration, with our rationale as to why we are proposing a different date.
Once we have confirmed a source of water delivery date with you, please ensure the Adoption Agreement is signed by all parties and sent back to us at [email protected], we will then sign it and provide you with a copy.

Please note: As per Appendix G1 of the sector guidance, the interval between the receipt of a complete, signed Water Adoption Agreement and the Delivery Date is subject to a minimum of 28 calendar days. If the valid signed Water Adoption Agreement is returned later than 28 calendar days prior to the Delivery Date, then this will move the Delivery Date to 28 calendar days after receipt of the signed Water Adoption Agreement.

Stage 5 – Construct main (SLP)

Each week, you’ll need to complete a ‘whereabouts’ form with details of any work being carried out near our water network. Please send this to us every Thursday, addressed to [email protected].

View the ‘whereabouts’ form

Before you commence work, we recommend you let us carry out a pre-start meeting on the site. During this session, we’ll talk through your proposal and agree how to achieve a smooth handover for adoption.

By a pre-start meeting isn’t a statutory requirement. However, you can request this service be emailing [email protected], please include the site address and annotate ‘pre start meeting’ in the heading. Once we’ve received your request, we aim to arrange the site meeting with you within 10 days.

Your source of water connection will need to be made by us as this is non-contestable work for your site. As advised in Stage 4, please state the date you need this connection to be made within the Adoption Agreement. Then you can proceed to construct the water mains using the agreed design.

Our SWS Site Guidance for Self-Lay and Requisition S41s document contains all the information you will need to know and understand when working on sites in the Southern Water area.  This information includes site preparation for mains, handover, flushing of mains, service connections, TBS, post service connection damage, stand pipes, chlorination of pipes, fire hydrant information and key Southern Water contact details.

Download the Self-Lay and Requisition S41s document

Please use the SLF-F4 Notification to start constructing a new water main’ form to notify us you’re about to start mainlaying. This needs to be submitted 14 days before any work starts.

Download the SLF-F4 Notification

Stage 6 – Connect and vest mains

Before the new main can be connected, it needs to be pressure tested and samples taken for bacteriological testing.

Please let us know ten days before the work is carried out by completing a Sampling Notification Form and sending the completed form to [email protected]. Please include the Southern Water Assistant Project Manager assigned to the development in the email. Please note, we require method statements and site risk assessment documents as part of the application.

Download the Notification Form

We’ll also need to carry out an inspection/audit of associated pipework and provide consent to connect/carry on commissioning. To arrange this, please complete Water Mains Connection Notification Form (Part 1 of the form). 

Download the Water Mains Connection Notification Form

Once you receive valid pass sample results, please send us the following information to [email protected] within one calendar day, as set out by Water UK’s levels of service:

  • If the SLP is accredited for construction of routine mains connections (CRMC) – submit CRMC paperwork via our Water Mains Connection Notification Form (Part 1 of the form). We’ll give our permission within five calendar days for the main's connection to be made. It should be carried out on the agreed date. You should confirm, within one day, that the connection went ahead as planned.


  • If the SLP is not accredited for CRMC or is classed as high risk – submit a completed Water Mains Connection Notification Form (Part 1 of the form) to [email protected], advising in the comments box that you wish SWS to complete the connection. We’ll make the main connection within 14 days of receiving the completed form.

In either case, you should also supply:

  • Type 2 Pressure Test and UKCAS accredited sample result certificates
  • As-laid drawings of the main which is being commissioned 

In addition, you should send a commissioning advice form and a vesting application (Part 2 of the form) to [email protected] within one day of the main's connection taking place. Once we have this, we’ll issue the declaration of vesting, this will be issued within five calendar days of receiving a fully completed application.

Download the commissioning advice form

Download the vesting application

We require a ‘walk off’ after connection to identify and resolve any defects or issues. Please request a ‘walk off’ by sending a completed commissioning certificate form, either prior to final reinstatement or two months prior to the end of the defect liability period, to [email protected]. After this, the mains will be part of our water network.

Download the commissioning certificate form

Stage 7 – Make service connections (Southern Water or SLP)

Please apply for your service connections via our Get Connected portal.
We will ask you about the proposed water fittings during your application.
If you are planning to self-certify your communication pipes and trenchwork you will need to send us the WIAPS (Water Industry Approved Plumber Scheme) accreditation details on your application.  We will issue consent for the connections and costing details within five calendar days of receiving a complete application.

Please note that receipt of your payment for the application is required for the five day administration period to commence. With your payment please include the reference number for your self-lay water mains adoption as this will allow us to match the payment to the application and progress with the administration.

Please also complete the notification of proposed works for the granting of consent form with the submission of the relevant application form. Receiving this form at the same time as the application will allow us to provide consent along with our costing details within five calendar days. 

Download the notification of proposed works for the granting of consent form

If you are planning to self-certify using a WIAPS (Water Industry Approved Plumber Scheme) certified plumber, please ensure that you notify us in the additional comments section of the application form.

After you receive plot costing, consent and payment information, you will need to return your customer acceptance form and make payment. Then once the site is ready we can complete an inspection and book attendance to make the connection. Please check that the main that is to be connected to is Operational.

If the SLP is making the service connection, prior to connection they must ensure meters are available/collected from us as required. The SLP should send us notification of intention to connect (at plot level) via the SLF F7 form, providing postal addresses from the local authority street name and numbering department. Then we can book in trench inspection, once satisfactory the SLP can carry out the connection and fit the meter.

Download the SLF F7 form

If you’re self-certifying, please follow our SLP Trench Inspection – Self-certification Policy
Download the SLP Trench Inspection – Self-certification Policy

Stage 8 – Notify service connections (SLP)

During the service connection application process we will ask you to confirm which plots have been connected, the date of connection and the meter serial number associated with that connection.
We will also ask for confirmation of the postal address of each new connection. We'll then register the new meter on the appropriate billing system.

Section 10 of the water sector guidance sets out the process for redress where a level of service metric has not been met by the water company.

We have created a redress document for ease of reference that captures both the redress guidance and link to the associated metrics.

Get in touch

Please send any correspondence about self-lay works to: [email protected].

Get in touch

Please send any correspondence about self-lay works to: [email protected].