Arranging a mains extension

Developments of a certain size may require a water mains extension.  The design and installation of which is normally undertaken by us.  We will offer you terms and conditions which includes the ability for the developer to install the mains and services to our design if undertaken using an accredited self-lay provider.

developmentsTo arrange for mains extensions on a new development please complete an Advance Payment Form, which can be downloaded by clicking here. A payment also needs to be included of the amount quoted in our Scheme of Charges (found on Our Promise page) on page 15 under Pre-development enquires.

In addition we will require the following:

Two no. 1:500 (or larger) true-to-scale plans, showing the layout of the development including positions of all buildings, roads, plot numbers, utility strips / footpaths and widths. These must be free of colour, dark shading or any proposed service layouts. They should also include a scaling pole and have contours and spot-level layers removed. In addition, the drawings need to show existing infrastructure to enable us to accurately plot our existing mains. If these drawings are to be emailed, they should be compatible with Autocad 2010 or PDF and saved to scale at your end.

  • A plan marked up to indicate the extent of the highway to be adopted by the Local Authority
  • A plan of the drainage layout including details of any permeable drainage areas
  • Information on the type of development i.e. domestic, commercial, mixed?
  • Estimated number of units and any proposed phasing?
  • Approximate date of planning consent?
  • Anticipated date when a start will be made?
  • For any non-domestic units, the peak flow and pressure demand
  • A detailed site history report (desk study), setting out all former uses of the site, including a full sequence of historic maps
  • Details of the location of any current or former fuel / oil storage tanks, chemical storage areas or tanks, and any other potentially contaminative uses on or adjacent to the site
  • Details of the initial pre-development site walkover survey identifying any areas of fly tipping, fuel / oil staining, fires sites etc.
  • A site investigation report including logs of investigation holes and chemical analysis results. Please note that to avoid delay in the processing of your application;
    • The Site investigation locations must be targeted to any areas of potential contamination, and / or madeground, but also provide good site coverage of the area across which the water mains are to be laid. If there is insufficient targeted investigation to assess the risk as to whether contamination may be present at the site which could pose a risk to drinking water pipes, then additional site investigation information will be requested.
    • The samples submitted for chemical analysis as part of the site investigation must be representative of where the pipes will be laid including samples taken of the topsoil, madeground and down to the planned pipe depth (usually 1m).
    • The laboratory analysis suite must include any contaminants identified as potentially present by the site history (desk study). As a minimum, even on a site described as ‘green field’ the analysis should include banded Total Petroleum Hydrocarbons and speciated Poly Aromatic Hydrocarbons.
    • Samples must tested in an accredited laboratory (e.g. UKAS & MCERTS). The detection limit for the test must be no higher than that specified in the Portsmouth Water Screening Criteria for the Use of PE Pipes
    • Details of any proposed contamination remediation.

Once these have been received we will be pleased to offer you terms for the mains extension.

Please note; Contaminants such as oils and solvents can permeate through certain types of water pipe. It is the responsibility of the developer to provide comprehensive and robust information on the potential for contamination to be present at the site, as described above. Portsmouth Water will then use the information supplied to determine the appropriate pipe material to be used in the construction of drinking water mains at the new development site.

For information on our Self Lay Water Mains and Service Procedure Guide click here

Please note that Statement of Costs for new build properties on developments where a new main has been requisitioned will only be released once the newly laid main has been commissioned and any easements on the land completed.

We also offer an Initial Enquiry for developments. This will provide a record drawing of our apparatus and give general guidance regarding the need for off-site mains and diversions. It will not, however, give any details regarding costs. To apply for an initial enquiry letter, please complete an Advance Payment Form, which can be downloaded by clicking here and sending with a payment of £65 plus VAT.

Please direct any mains extensions enquiries or initial enquiries to [email protected] or telephone 023 9224 9327

If you would like a record drawing of our apparatus only, please direct your enquiry to [email protected] or telephone 023 9244 9082