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
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.
Building Over Non-Critical Public sewers
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)
Piling Works Near Public sewers (within 15m of a public sewer)
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.
Building Over or Near a Public Sewer Agreement
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 firstname.lastname@example.org
- 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.