New water main

If you are building multiple domestic or commercial properties on a site that will have new road access you will probably need a new water main to be laid to service your site.

Do you wish to consider a self-lay or NAV?

This main, and the services to each property, can either be laid by ourselves as Southern Water or by accredited Self-lay Providers (SLPs). We support mains laid by Self-lay Providers and adopt independently installed mains and services once they are commissioned.

New Appointments and Variations (NAVs) can also be used to service a site and replace the incumbent water or sewerage company for a specific geographical area.


New Water Mains through us

If you would like to request a new water main through us, Southern Water, then we often refer to this as a ‘Section 41 Water Main Requisition’. Below is a guide on what you need to do when making a water main requisition application, including links to make an application via our GetConnected portal.


Steps that we'll take to get you connected

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

  1. You apply online and pay your application fee

    You review the quote, accept and pay for the construction works, along with filling in our water regulations questionnaire.

  2. We provide your quote

    We carry out a site survey and produce your project quote within 28 days (42 days for complex projects).

  3. You accept, sign and pay for the works

    You review the quote, sign and pay for the works in order to proceed.

  4. We produce a design and arrange a meeting

    We produce a detailed design of your new water main and arrange a meeting to confirm the start date and agree the schedule for the work.

  5. You may need to provide a chlorination certificate

    We schedule our work and begin construction of the new water main. You may need to provide a chlorination certificate to be reviewed by our team (greater than 63 mm).

  6. We complete the new main connection

    We complete connection of the new main to our network within 90 days.

  7. You can apply for individual connections

    After we are connected, you can apply for individual service connections. See our Water Connection service.

Stage 1 - Make an Application

All water main requisition applications should be made by applying via our GetConnected portal.

Before you apply, please read our water main requisition guidance and Terms and Conditions which will take you through the process and what is required, including:

  • Site Location and Layout Plans.
  • A CAD drawing.
  • The pre-construction information pack.
  • A Contaminated land assessment form with an appropriate soil report and documentation.
  • Topographical information for the site.

Download water main requisition guidance

View our Terms and Conditions

Download the Contaminated land assessment form


Furthermore, it is important you include and confirm the below in your application (where applicable), as these are the most common reasons we need to ask for more information:

  • A plan (.pdf) showing the location you would like to connect into our network.
  • A plan (.pdf) of any permeable paving on your site and a drawing (.dwg) showing the construction details in relation to this.
  • The latest site plan (.pdf) showing all the service entry points (where the water enters each building) including any bin store or landlord supplies.
  • Confirmation of the status of all roads/highways on your development will remain private.
  • Confirmation of who will be responsible for the onsite trench excavations, backfill & reinstatement.
  • A completed occupancy table.
  • A service margin plan (.pdf).
  • A plan (.pdf) of your development’s future stages including what is the planned use for the site, the number of properties and the likely water demand in l/s.
  • A fully completed contaminated land risk assessment, which needs to be signed by a competent professional and have page 7 of the risk assessment summary completed.


The application cost is variable as to the number of units you are applying for, you can find out more below:

0 to 50 units - £1,628 

For 51 to 250 units - £1,716

For 251 to 500 units - £1,924 

For more than 500 units - £2,222

(All including 20% VAT)

Once your application has been made, our team will review the information submitted and we will respond within 5 days to confirm that the documentation is complete or ask for more information if required.

Stage 2 – Receive Construction Costs and Design

Within 28 days (or 42 days for complex sites) we will evaluate the construction costs and design, before sending you your quotation for the works to be carried out, this will include:

  • A quotation in the form of an offer letter.
  • Associated design drawings (.pdf).
  • A Section 41 agreement and acceptance form.
  • Our Terms and Conditions.
  • A calculation sheet detailing how we quoted against our standard connection charging.

The quotation is valid for three months, after which you will need to request a requote detailing any changes to the site so we can update your quotation as required. If our charges have changed, we will also update the quotation to reflect this.

Stage 3 – Awaiting Acceptance and Payment

Once you have received our offer and are ready to accept the quotation and pay, you will need to do the following:

  • Sign and return the Requisition Agreement.
  • Sign and return the Acceptance form.
  • Provide us with a copy of your Pre-Construction Information pack.
  • Make payment for the works.

After completing the above, we will return a counter-signed agreement and then pass the site to our Project Delivery team who will assign a Project Manager as a point of contact for the next steps in the process as you await construction.

Stage 4 – Pre-Start Meeting and Scheduling

After acceptance we will arrange for a pre-start meeting to be held at your development site, in which we will confirm the start date on site, the number of main laying phases and agree a schedule for the programme of work required.

If you are carrying out the excavation work for the new water main on site, you will need to prepare the trench following the route within the construction design drawings supplied by us.

Stage 5 – Work Scheduled

Once the work has been scheduled and the onsite dates confirmed, we will begin construction of the new water main. This will include the need for a chlorination certificate which will be reviewed by our Scientific Services team to give approval for the connection.

If there are multiple phases, we will coordinate with you to organise a new pre-start meeting and scheduling for each phase.

Stage 6 – Connect and Apply for your Service Connections

Once the connection is complete, you can apply for your individual service connections through our water connection team.

Apply Now


New Sewer Main

If you are also considering building a new sewer main for your site, you can either build the main yourself and have it adopted by us through a Sewer Adoption or consider requesting a Sewer Requisition.


Still have questions? We are here to help

We understand that all projects are different, and it might be hard to understand what the right and most cost-effective option is. Please visit our Frequently Asked Questions page for more guidance or simply request a call back from our helpful team. 

Request a call back

Apply Online

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