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Close Proximity to Assets (Water & Sewers)

Realignment of Public Sewers

Realignment of Public Sewers

Guidance Notes

Article 247 – Water and Sewerage Services (Northern Ireland) Order 2006 (as amended by the Water and Sewerage Services Act (Northern Ireland)) 2016.

These notes relate only to sewers and not to watermains. 

Please note: 

Although we will consider every case sympathetically, it is possible that permission to realign public sewers will not be given. The fee for a realignment of the public sewers will not be refundable following technical assessment if the application is refused.

You should read the following carefully prior to applying to realign a public sewer. You must ensure that any project managers, consultants or contractors acting upon your behalf are aware of the costs, requirements and timings associated with sewer diversion works and that sufficient time has been allowed for the completion of the sewer diversion prior to you starting to build on site.

The design of the realigned section of the sewer must meet the standards as defined in sewers for Adoption (NI) Current Addition. The hydraulic design of the proposed sewer realignment must match (or exceed) the hydraulic design and self-cleansing regime of the existing sewer. 

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

Following receipt of the application to realign a public sewer, NI Water will assess your proposals and determine if a sewer realignment is possible and notify you in writing of the fees and bond prior to formal approval. The bond/refundable cash deposit, as a surety, equal to the estimated construction cost of the works will have to be setup/paid prior to authorisation of the Sewer Realignment Agreement. 

Realignment of a public sewer in private lands or unadopted streets can be completed by the developer/housebuilder, provided a bond security/deposit is in place with NI Water’s written approval. Where a proposed diversion is in a public street, the developer will not be permitted to carry out the work unless they use an accredited Street Works Licensed Operator and is able to obtain a valid Street Works Licence from DFI Roads for that specific job.

 If your contractor carries out the works, at no cost to NI Water, we will refund 80% of the bond/cash deposit once the works have been completed to our satisfaction and CCTV has been undertaken by NIW. When 12 months has elapsed following the completion and making good of any defects, the developer should make a request in writing and include ‘As Constructed’ drawings with levels in relation to the Ordnance Datum (Belfast) and a manhole schedule, to have the remaining 20% released.

Lateral Drains and Additional Requirements

 Prior to commencing any work on site, you must identify the position and operational status of all sewers or lateral drains connection to the section of sewer which is to be abandoned. Should lateral drains be found, you must obtain the written consent and authority of the owner of the lateral drain to reconnect their property to the new sewer. 

You must ensure that the premises affected by the lateral drain continue to be drained with at least equal effectiveness once the works have taken place.

The approvals should be enclosed in your initial submission.

We will also require a method statement detailing how you are intending to deal with existing flows during the course of the works

Please note that is not permission to discharge

  • Four sewerage into road gullies surface water sewers, ditches, the trench or watercourses
  • Ground water into public sewer
  • Surface water into the foul/combined water system

Buildings must be located a minimum of three metres or 1.5 times the depth (whichever is greater) from the realigned sewer. In circumstances of greater depth, large diameter sewers, unusual ground profile, poor ground conditions or material, a greater distance may be required.

On completion of the works, the redundant section(s) of the existing public sewers will be made safe by removing them from the ground, or by agreement, a suitable method has been employed for making the redundant section of the pipework safe.

Upon being notified of the completion of works, the developer shall supply to the Company, two sets (or more if requested), of ‘as constructed’ drawings showing the sewer realignment, together with operating instructions/maintenance manuals for any pumping stations associated with the works. On completion of the works, NI Water will undertake a CCTV survey

The Health and Safety File, as required by the Construction (Design and Management (Amendment) Regulations(Northern Ireland)) 2007 as amended or replaced, will be required.

When making your application for a realignment, we will require two copies of the following documents:

  • Site Location Plan 1:1250 Ordnance Survey based may (or 1:2500 may be accepted) with the site boundary clearly indicated in red and relative to an existing feature. Any other land owned by the applicant should be shown with a blue line around its boundaries, and if a public right of way exists within or adjoining the site, it should be outlined in green.)
  •  Site Layout Plan @ 1:1100 or larger, showing location of existing sewers and manholes.
  •  Longitudinal Section showing existing pipe size, gradient, material depth and manholes.
  • Longitudinal Sections of proposed sewer realignment, proposed pipe size, gradient, material depth and manholes
  • Programme Plan of Works.
  • Method Statement for Construction.
  • Geo-technical investigation report/Ground investigation report.
  • Legal permission to lay in 3rd party lands.• Proof of permission from DFI Roads for the developer to lay the sewer in the public roadway, where applicable.

No realignment works should proceed until such times as the formal agreement has been issued.

Should you require any further information or assistance, please contact Developer Services:

Developer Services – Servicing Team
Northern Ireland Water
Ballykeel Office
188 Larne Road
Co Antrim BT42 3HA

Telephone: 03458 770 003
Email: developerservices[AT]niwater[DOT]com

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