It is an offence under Article 236 of the Water and Sewerage Services (Northern Ireland) Order 2006 (as amended Water and Sewerage Services Act (Northern Ireland) 2016), to realign, build over or near watermains, public sewers, pipes and associated works owned and maintained by NI Water unless with the prior consent by NI Water.

If you have located or have reason to believe that a public sewer is within 3m or 1.5 times the depth (whichever is the greater) or beside your proposed works, and construction is proposed within the Protected Strip you MUST consider relocating your building.

If you have considered all the alternatives and the only option appears to be to build over or near the public sewer and the sewer in question is not a critical sewer, you should forward your proposals to us for assessment using application form SBO-A236.

It should be noted that Northern Ireland Water will not consider a proposal to build over a public sewer for a new building.

In order to adequately assess the application, it will be necessary for you to determine the exact location and condition of the affected sewer(s).

Where this is not possible Northern Ireland Water may be willing to determine the location on site. However, this may be at your expense.

The current fees and charges associated with this service in accordance with the current Scheme of Charges are:

● Application Fee - this includes appraisal of your proposals (non-returnable);

● Inspection Fee

Please note:

Although we will consider every case sympathetically, it is probable that permission to build over sewers which are classified as critical sewers will not be given.

It may be possible to build over non-critical public sewers, which often run along the back of older properties and are affected by extensions to the rear of the property. In most instances building over/near these public sewers will be permitted, providing that certain structural protective measures are taken. The standard protective measures are as follows:

• CCTV Survey will be required to determine the existing condition and location of the affected public sewer;
• Foundations must be taken down to a minimum of 150mm below the public sewer invert level. No structures (footings, walls etc) running parallel, or adjacent to the line of the public sewer will be allowed within 500mm of the public sewer (in plan); and
• Crossings must be supported using pre-cast (or adequately designed cast in-situ) concrete lintels/beams. (Please refer to the ‘Typical Detail for Building Over a Public sewer’ on page 3)

• Critical Public sewers are usually defined as large diameter strategic public sewers but may also be classified by material, depth and/or location.
• Under no circumstances is construction allowed directly over a pumping main. Restrictions WILL also apply as to how close you can build to such public sewers.

Where piling works are being carried out care must be taken to avoid any damage to the public sewers. The position of the public sewer MUST be established by electronic survey. Should the survey suggest that the public sewer is likely to be within 15 metres of the piling works, trial holes may be required to establish the exact location of the public sewer. Piling systems must be chosen so that resultant vibration is kept to a minimum. A suitable method statement, inclusive of the measures to be taken if the public sewer is damaged, must also accompany the application. 

• You must submit the application form SBO-A236 via email to developerservices@niwater.com including all of the required information. 
• Northern Ireland Water Ltd asks for details of:
  • Any mortgage on the property: 
    • in order that we can ensure that the mortgage company joins into any build-over agreement, to avoid a situation where they do not do so and they subsequently repossess the property and sell it  on. If this happened, the mortgage company and the subsequent purchaser could say that:
      • they (in the case of the mortgage company) or the mortgage company from whom they acquired  the property (in the case of a subsequent purchaser) had not signed or been aware of the  buildover agreement.
      • the buildover agreement was not therefore binding on them.
    • The house insurance ( must include buildings cover): 
      • as any home insurance company would want to be informed that the homeowner was entering into  an agreement with NIW to build a structure over or near a public sewer in relation to a property  which was insured with them.
• Typical requirements for the associated documentation are:
  • The drawings(s) should include: 
    • Site Layout:
      • Be at a scale of 1: 100 or greater.
      • Show the location of existing public sewers and MH’s: 
        • Foul to be shown in red. 
        • Storm to be shown in green. 
        • Combined to be shown in magenta.
      • Show the extent of existing buildings and the proposed new construction (and any other structures that may cause a loading on the public sewer).
      • Indicate changes in Ground Levels.
      • Existing public sewer replacements, to include tie in details to the remaining public sewer.
    • Longitudinal Section:
      • The sections should show:
        • Pipe size. 
        • Gradient. 
        • Material.
        • Manholes.
        • Invert Levels and Cover Levels to Ordnance Datum Belfast. 
      • Existing public sewer replacements, to include tie in details to the remaining public sewer.
    • Protection detail at crossover / potential loading locations:
      • This detail should be site specific, detailing the structural protection to prevent loading on the  public sewer.
    • Please include the floor construction method if the proposal is to build over the public sewer:
      • if it is proposed to have a concrete floor, only suspended concrete floors will be permissible.
  • The drawings should only show details that are relevant to the application, ie: 
    • The location of the proposed Build over/ near in relation to the public sewer. 
    • The proposed protection detail specific to the proposal. 
    • The public sewer with the colour coding as listed above with any private drainage shown in black.
  • If it is proposed to replace the pipe or construct a manhole on the public sewer you must submit a Method  Statement for the work.
  • If you are not proposing to replace the pipe, a Method Statement will be required in case the public sewer is  damaged during the construction process.
• Your application will be checked during a triage process and if incomplete will not progress until such times as all of the requested information has been received. 
• Once your application has completed the triage process you will receive a request for payment. 
• On receipt of payment your application will be assigned to a Wastewater Approvals Technical Adviser

• Northern Ireland Water may request a Structural Engineers Report at the developer’s expense.
• Multi-applications for proposed building over proposals that are in the same location and on the same sewerleg will attract a discount for third and subsequent applications. Further Details are available in the currentScheme of Charges and the application form.

Once the Wastewater Approvals Technical Adviser has assessed your proposals and agreed the associated detailed design drawings, they will issue a Building Over or Near a Public Sewer Agreement via email.

When you receive the Building Over or Near a Public Sewer Agreement 

• you will be required to print the agreement and gain all of the necessary signatures prior to scanning and emailing it to developerservices@niwater.com
• if there is any loan / mortgage on the associated property, the Loan / mortgage provider MUST sign the Building Over or Near a Public Sewer Agreement prior to it being returned to NIW.
• you must hold and provide current Home Insurance details which must include buildings cover.
• No work must commence on site until the Assessment and authorisation of the Building Over or Near a Public Sewer Agreement has been completed and the authorised Agreement returned to the applicant.

• You MUST submit an SBO-A236-Insp inspection application form to developerservices@niwater.com to request a site inspection, allowing 10 working days’ notice.
• NIW will triage the inspection application, and if all of the required information has been provided will issue a request for payment of the Inspection Fee. 
• On receipt of the Inspection Fee your application will be assigned to the Wastewater Approvals Technical Adviser who will be in contact to arrange a mutually suitable date for the inspection.
• Any excavation and structural protection to the public sewer must not be backfilled or covered until inspected by NI Water. If the excavation has been backfilled, you must excavate the locations of the structural protection prior to the agreed inspection date.
• If the works are deemed to be satisfactory you will receive a copy of the Final Certificate of Satisfactory Completion of the Building Over / Near a Public Sewer along with a stamped copy of the associated As Constructed drawing.

Please note:

• NI Water may request a Structural Engineers Report at the developer’s expense.
• Multi-applications with the same owner / lender for proposed building over proposals that are in the same location and on the same public sewer leg will attract a discount for third and subsequent applications. However, each property will be processed under a separate Building Over or Near a Public Sewer Agreement, with the associated Inspection fee. Further details are available in the current Scheme of Charges and on the application form. 
• Multiple properties with different owners/lenders must have a separate application.

Should you require any further information or assistance please contact Developer Services Servicing Team

Telephone: 03458 770 003

Email: developerservices[AT]niwater[DOT]com

For more information on how NI Water lawfully processes personal data please view our Privacy Notice at; https://www.niwater.com/privacy/

• Foundations must be below the sewer invert level. No structures (footings, walls etc.) running parallel to theline of the sewer will be allowed within 3.0 metres or 1.5 times the depth of the sewer (whichever is greater),unless by agreement of the Operations Technical SupportManager.
• The exact location and condition of the affected sewer will need to be determined.