NIW has a legal requirement to maintain a wholesome supply of water to its customers.
To ensure service delivery NIW needs to be able to maintain, repair, refurbish and replace water mains as and when the need arises. This requires access to our infrastructure at all times, and is supported with legislation under Article 236 of the Water and Sewerage Services (Northern Ireland) Order 2006.
The following guidance sets out NIW’s requirements to deliver its statutory duties, mitigate potential damage to property and minimise Health and Safety Risks should the infrastructure fail.
The minimum clearance distances detailed below are primarily determined based on operational requirements, and the strategic importance of the asset within the Network; however, other factors such as site-specific topography, high-pressure systems and depth of the main may determine greater clearance distances.
|Pipe Diameter||Minimum Access Distance either side of pipe|
|Up to 180mm||3 metres|
|181 - 350mm||4 metres|
|351 – 600mm||6 metres|
|Greater than 600mm||Requires consultation and approval from NIW|
Note: Table assumes pipe at nominal cover to crown of <1.5m
NIW acknowledges that there may be locations across the Province where buildings have previously been sited within the access/protection zone, this is no longer acceptable unless approved by NIW following full consultation prior to planning approval (see Exceptional Approval below).
Design of New Developments
Where a development is planned in the vicinity of existing water mains, the onus is on the Developer to carry out exploratory excavations to determine the exact line and level of the pipework prior to finalising the proposed layout for the site. The layout should be designed to ensure that NIW infrastructure is located within a verge, road or public green space within the site; the design should not result in the land, under which existing mains are located, becoming private property.
Building over a water main is not allowed under any circumstances
Any proposed increase in ground levels in the access/protection zone needs to be agreed with NIW to avoid overloading and settlement of the pipework or hampering of operational repairs.
NIW recognise that in some circumstances that site-specific conditions cannot afford the provision of the distances specified above. In these cases it may be possible for NIW to grant ‘exception approval’ provided an engineering solution is put in place to protect both the pipework and the proposed building(s) plus still permitting access for any future maintenance or replacement work required under our statutory duties. The Developer should therefore consult with NIW as soon as possible and prior to seeking planning approval for the site.
Provided reasonable access to NIW assets are maintained, engineering solutions can include:
- the construction of foundations at a level below NIW infrastructure to protect the integrity of the building
- provision of a protective structure to avoid undermining of buildings should the main fail
- any other proposal that would mitigate the risk to both NIW assets and the proposed development
If Access/Protection Zones cannot be achieved diversion of NIW infrastructure may be an option provided it is considered practical and the Developer is prepared to meet all costs involved.
This will be subject to a separate formal agreement with NIW covered under Article 247 of the Water and Sewerage Services (Northern Ireland) Order 2006.
Customers wishing to apply to divert a public water main should submit a completed WD-A247 Form
The Developer should determine line and level of the existing watermains and put in place mitigating measures as required to avoid damage during construction. If cover to the watermain is less than750mm the Developer should contact NIW asap. In some cases, there may be a need to design and construct an engineering solution to protect the pipework from any future loading.
If any excavation work is required within the access/protection zone and close to the water main, the Developer should submit a Method Statement and Risk Assessment to NIW’s Water Performance Team at WPL[DOT]assetperformance[AT]niwater[DOT]com, 21 days in advance of the works. This will allow time for liaison with local Operational Staff and the preparation of contingency measures.
Access to the protection zone shall be kept clear and unrestricted at all times i.e. construction materials and excavated material should not be stored there.
Notification to Future Property Owners
NIW requires Developers to notify future property owners of the land-use restriction near water mains, by including the restrictions within the Deed of Conditions such that they remain visible to all future property owners and are in the public domain.
NIW has a statutory duty to ensure its operations do not pose a risk to others. It is NIW policy to legally contest any infringements of above.
If you have any queries please contact the Developer Services at:
Developer Services - Servicing Team Northern Ireland Water
188 Larne Road
Co Antrim BT42 3HA
03457 44 00 88