About New Mains

Arrange a date for mainlaying

If we are installing the mains for your development, you will need to contact us to arrange for the mainlaying to be included in our mainlaying programme.

You will have been given the name and contact details for the Distribution District Manager/Network Site Agent responsible for the mainlaying on your site when we wrote to you with the finalised details for the scheme. Once you have informed us which payment option you prefer and/or paid the financial contribution for the mains, please contact the relevant Distribution District Manager/Network Site Agent to arrange a mainlaying date.

Normally our mainlaying crews are booked-up about two months in advance, but occasionally we get cancellations.

Trench Specification

When developers requisition mains from us they are encouraged to provide the trenchwork for any standard mainlaying within their site boundary; we will carry out mainlaying within the public highway or third party land. Developers who choose to provide the onsite trenchwork should ensure that they adhere to the requirements listed below:

• Developers should ensure that the trenches they provide allow for all mains to have 900mm of cover once the formation of the road/footpath/verge (under which the main is to be installed) is completed. This is a minimum figure; slight increases in cover may be allowed but must be agreed in writing prior to the installation of the main. Kerbing should be installed to give an indication of line and level for all installations.

• The width of the required trench will primarily be dependent upon the diameter of the pipe to be installed. Developers will be advised of the required width during a site meeting which will take place prior to the mains being installed, however the following is an indication of the minimum trench widths in which we will install mains:

   

   

  Diameter of Main (MM)	Minimum Trench
  63 or 90	390
  125	425
  180	480
  225 or 250	550

   

         

• Mains are to be laid along the lines shown on the plans we have provided. Trenches should therefore be positioned to allow for this. Any changes to the layout should be agreed with us prior to the proposed installation date, so that delays can be avoided. Our mainlaying crew will not start installing mains if the trenchwork provided does not correspond to the plans that they have been given.

• Pipe installations should follow the National Joint Utilities Group’s (NJUG’s) guidelines on the Positioning and Colour Coding of Underground Utilities’ Apparatus so that a minimum horizontal clearance of preferably 200 mm, or at the very least 150 mm, is provided between the wall of our pipeline and other utility apparatus, including chambers. Should this not be practical, an alternative arrangement must be agreed with us in writing prior to the start of the new mains installation.

• All work should be carried out in accordance with HSE guidance HSG47 and HSG47. Excavations should be supported, where required, and safe for the duration of our crew’s visit. Any plant working on the site must maintain a safe distance from the trench. Our mainlaying contractor may require you to sign a permit to work before they enter your excavation.

• Sufficient trench is to be provided to enable our mainlaying crew to carry out uninterrupted mainlaying. We will charge for any waiting time. Additional payments will also be due if we are unable to complete the installation and have to return to site to finish

• We will install both a 100mm bed and a surround that extends to 150mm above the crown of the pipe. Developers should make sufficient stone dust available to our mainlaying crew for this installation.

• After a new main is laid, a period of around two weeks is needed before the main can be made operational. This is to allow for the main to be chlorinated and for bacteriological and pressure tests to be carried out. During this period developers may completely backfill the trench, provided that they re-excavate around the connection point prior to our mainlaying crew’s return to site to carry out the connection. Developers should bear in mind that it may be necessary to re-excavate along the entire length of the main, if a problem with the main is detected during testing.

Phasing

On larger sites it is often beneficial to phase the installation of any required mains. This does not mean that you have to apply for each phase separately – they can all be covered by a single application. You might want to consider phasing the installation of the mains if:

• Certain parts of the site will require water well in advance of other parts. We will not install mains and then leave them “dry”. We aim to get them into service as soon as possible, normally within 2-3 weeks. Once mains are made live we need to ensure that the water in them is turned-over on a regular basis so that water quality is maintained. Mains are therefore not normally installed too far in advance of when water will be required.

• It will not be possible to access all of the site for mainlaying at once because of scaffolding or other obstructions.

• Line and level will not be available on certain parts of the site. The kerb brace should have been installed, prior to our visit, in any roads in which mains are to be installed.

You will be asked to indicate how you wish the mains to be phased when you apply. At the very least, you will need to tell us how much main you want us to install in our first visit to site. When deciding on the phasing you require please consider not only when each plot requires a water supply, but also when each road/footpath will be available for mainlaying. The phasing you mark up on the plan you send to us should correspond to the phases you will be asked to list on the application form.

We understand that plans change so if you do need to alter the proposals, please contact us as early as you can so that we are able to revise and reprint the plans for our mainlaying gangs.

Any alterations should be agreed in writing before our mainlaying gang is due on site, so that delays can be avoided. Our mainlaying gangs will not start installing mains if they will be unable to finish all of the mainlaying that they have been instructed to install either because there are obstructions, a lack of line and level or insufficient trenchwork available. We will charge for any abortive visits and waiting time.

When extra visits are required, additional charges will normally be payable as we will have to install additional temporary fittings between the sections of main and carry out additional disinfections, pressure tests and chlorinations. Depending on the size of the main the additional costs can be up to around £2,000 per additional mains connection required. We will also charge a re-design fee whenever plans or costings have to be revised.

Contaminated Land

Our policy on contaminated land and pipe choice was revised in spring 2013. The information we require from developers, for all sites, has now changed considerably.

Site Assessment Reports (SARs) are required for any sites where you want the installation of standard polyethylene pipework to be considered. The production of a SAR does not, however, necessarily require intrusive investigations.

Please see our guidance leaflet for more information.

Resources

Guidance on Contaminated Land

Timescales

Applications for new mains should be submitted a minimum of 12 weeks before you require mainlaying to commence onsite, regardless of whether you want to requisition the mains from us or Self-Lay them. We are often unable to begin processing applications because when they are submitted to us because they are not complete, so please ensure that you fill in the whole application form and attach all necessary additional information and plans.

In many cases you will be provided with details of the finalised scheme, financial information and, where applicable, a self-lay agreement, within 4 weeks. This period may, however, be extended by a month or more, if it is necessary to undertake a significant investigation into how the development can be supplied.

If you are applying to Self-Lay infrastructure you should allow plenty of time for the agreement to be circulated around the relevant parties (developer, SLP, land owners etc.) for signature. Mainlaying should not commence until all parties, including Bristol Water, have signed the agreement.

Work on the installation of the mains (both requisitioned mains and the non-contestable sections of mainlaying for Self-Lay schemes) can normally commence around eight weeks after receipt of payment or confirmation of payment choice. If it is necessary to install mains through third-party land or undertake extensive or disruptive mainlaying within the public highway, then we may be required to provide up to three months notice to the affected party. We would not normally submit this notice until payment or confirmation of payment choice has been received. Environmental considerations may also affect installation dates.

Wherever possible we will endeavour to reduce all of these time periods to meet developers’ programmes, however you should be aware that some of them are not within our control. You are advised to apply as early as possible.

The mainlaying itself can take anything from a couple of days to several months, depending on how much main needs to be installed, the diameter of the main and the location of the new main.

Before the main can be commissioned, it needs to be cleaned and disinfected. Samples will be taken from the main. The analysis of these samples can take up to two weeks, so there will be a two-week gap between the mainlaying being completed and the new mains being connected up.

Trees

No trees or large shrubs should be planted over or within 3.0 metres of our apparatus, or the proposed route of our apparatus, unless suitable root restriction methods are taken. If root restriction is to be considered it should extend at least 1.5 metres below finished surface level, in which case the minimum clearance between the wall of our pipeline/apparatus and the root restrictor can be reduced to 0.5 metres. Developers should consult an arboriculturist for advice on the minimum clearances required between root protectors and trees/shrubs.

Should our pipeline have to pass between two trees/large shrubs, a minimum clearance of at least 3.0 metres must be maintained between their respective boles, even where root restrictors are installed.

Developers should include a planting layout with their application.

When installing mains in the vicinity of existing trees we will follow volume 4 of the National Joint Utilities Group (NJUG) guidelines – Guidelines for the Planning, Installation and Maintenance of Utility Apparatus in Proximity to Trees.