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Pre-Development Enquiry

Multi Unit Developments & Commercial

Application & Guidance

Assessment & Response

  • We will assess your application in detail.
  • Our response will outline the availability and capacity of our existing public sewer and water network.
  • Our response will also explain anything required from you at this stage.

Next Steps

Pre-Development Enquiry


Pre Development Enquiry (PDE) application needs to be submitted as soon as is practicable and prior to any formal planning submission.

Completion of all sections is essential in order to avoid return of your application. Please refer to our guidance details below before completing your application.

The Pre-Development Enquiry Response will advise the applicant on the following:

  • Status of receiving Waste Water Treatment Works
  • Current availability of water and sewerage infrastructure to accommodate proposed flows – foul, storm and water
  • Anticipated points of Connection.
  • Proximity to Existing Assets within the site boundary (& referral to required assessment of protective measures)
  • Further requirement (as applicable) for the developer to apply for a Water and/or Wastewater Impact Assessment.
  • Further requirement (as applicable) for the developer to apply for an Odour Assessment
  • Copy of NI Water Mapping records relevant to the site (Please Note Disclaimer).

Pre Development Enquiry (PDE) applications can be made to NIW to obtain information about the availability and capacity of water and sewerage infrastructure to service future development. NIW will advise if the existing infrastructure can accommodate the proposed development and provide detail on the anticipated points of connection. During a PDE assessment, NIW may identify potential capacity or odour issues which require further analysis. As a result a further detailed assessment may be requested by NIW. This is known as an Impact Assessment.

Note: NIW is committed to delivering new economic and housing growth, sustainably. In some cases, where our existing infrastructure is overloaded, NIW may have to refuse/defer new connections in order to protect the environment and our customers from flooding. The applicant will be notified of specific development constraints as part of the PDE process.

All applications MUST include the following:

  • A Site Location Plan 1:2500 map (LPS ACE map will suffice) 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. The 12 figure OS Grid Reference (x,y co-ordinates) of the approximate mid-point of the site is also required to allow the location to be accessed quickly and to avoid confusion when viewing on our map server.
  • Planning references of all extant and live planning applications
  • Extant Planning – if your site has extant planning and the approval date is more than 5-years, you must provide a Certificate of Lawful Existing Use or Development to confirm that the planning is extant.



  • Guidance on Foul Sewer Design – In accordance with Sewers for Adoption NI 1st Edition (Section 2.5 – Hydraulic Design –Foul Sewers & Lateral Drains)
  • Applicant to clearly mark proposed connection points on Site Layout Plan.
  • Applicant to clearly demonstrate on application form how proposed foul discharge rate has been calculated. As per Sewers for Adoption NI 1st Edition (Section 2.5); the proposed design flows for gravity foul sewers for residential developments should be 4000 litres/unit dwelling/ per 24 hours.
  • Applicant to clearly mark any existing connection points on Site Layout Plan indicating if they are foul only or combined and provide associated calculations.

Surface Water:

  • Applicant needs to demonstrate clearly for full bore surface water design, how the proposed discharge rate has been calculated (i.e. impervious areas (Ha) and rainfall intensity (mm/hr)).
  • For Guidance on Storm Sewer Design – In accordance with Sewers for Adoption NI 1st Edition (Section 2.7 - Greenfield Discharge)
  • Greenfield discharge/approval is governed by DfI Rivers. Applicant to demonstrate clearly on application form how proposed discharge rate has been calculated and provide evidence of correspondence with DfI Rivers.
  • Clearly mark proposed connection points (discharge location) on Site Layout Plan.


  • It is important in the application that the applicant ensures that the Peak Flow Rate (l/s) and average ‘Continuous Flow Rate’ (l/s) requested are reflective and realistic.
  • Please provide supporting calculations/information on how the Peak Flow Rate (l/s) and average ‘Continuous Flow Rate’ (l/s) have been arrived at.


  • Please note that NI Water does not have a duty to provide infrastructure specific to firefighting, i.e. hydrants or additional mains capacity.

Water Loading Units Table

  • Please ensure this is fully populated for all proposed Commercial and Industrial development.

Trade Effluent Discharge

The Developer must contact NIW Trade Effluent Team to seek consent for a Trade Effluent discharge. The discharge of Trade Effluent without consent is an offence and may result in legal action being taken. Further information and a Trade Effluent Application Pack can be downloaded from the NIW website at

Returning completed forms

The PDE Response will be valid for a period of 18 months and should formal approval to make connections to the public water and sewerage networks not have been granted by NI Water within this timescale, a further PDE will require to be submitted to ensure that capacity currently identified as being available to serve this proposal, still exists.

Please return completed form(s) and appropriate fees to:

Developer Services Servicing Team

Northern Ireland Water

Ballykeel Office 

88 Larne Road 

Ballykeel, Ballymena 

Co Antrim BT42 3HA

Tel: 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;

Pre-Development Enquiry

Nominal Fee and response within 28 working days

We will review existing network and treatment capacity and the anticipated points of connection for water and sewerage services. We will also complete checks and advise of existing assets within the site boundary or if the site is within an odour boundary for one of our assets.

We will then provide a written response including a copy of our records adjacent to the site.

If there are no constraints you can then progress to make a formal planning application knowing that NI Water will be able to support your planning application and provide a positive response to your planning application

If there are constraints you will be asked to submit an Impact Assessment Application for Water, Wastewater or Odour and NIW will work with you to identify potential solutions. For site where we identified constraints NI Water will recommend to planners that the planning be refused until you have completed the necessary impact assessments and agreed a developer led solution for the capacity issues.

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