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Impact Assessment

Wastewater Impact Assessment

Wastewater Impact Assessment


The Wastewater Impact Assessment application is a referral application following the Pre-Development Enquiry process and needs to be submitted as soon as is practicable and prior to any formal planning submission. 

Failure to complete all sections will result in the return of your application. Please refer to our guidance details below before completing your application.

NI Water provides a Wastewater Impact Assessment service to assist developers in identifying any possible constraints that may be associated with servicing a development site in terms of wastewater infrastructure. The Impact Assessment can assist developers in understanding the potential costs and timescales involved in servicing a site prior to land acquisition or in advance of the submission of a planning application.

Should you wish to take advantage of this service, please complete the Wastewater Impact Assessment application form (WW-IA)and forward with the appropriate fee to the address below.

On receipt of the fixed fee, NI Water will produce a site specific development solution engineers report detailing potential developer funded solutions to overcome Wastewater capacity constraints and help facilitate new development in areas where capacity is limited.

An indicative construction cost of solutions, such as off-site infrastructure or network upgrading, will be provided.

NI Water will endeavour to provide you with a development solution engineers report within 65 working days of receipt of a complete application.

The Wastewater Impact Assessment process does not guarantee the applicant connection to the NI Water Wastewater network, nor can NI Water commit to specific construction timeframes.

Wastewater details

  • Foul:
    • Clearly mark proposed connection points on Site Layout Plan.
    • As per Sewers for Adoption NI 1st Edition (Section 2.5); the proposed design flows for gravity foul sewers for residential developments should be 4,000 litres/unit dwelling/ per 24 hours. Applicant to demonstrate clearly on application form how proposed discharge rate has been calculated.
    • Clearly mark any existing connection points on Site Layout Plan indicating if they are foul only or combined and provide associated calculations.

Surface Water:

  • Clearly mark proposed connection points (discharge location) on Site Layout Plan.
  • For ‘full bore’ surface water design the applicant needs to demonstrate clearly how the proposed discharge rate has been calculated (i.e. impervious areas (Ha) and rainfall intensity (mm/hr)).
  • Greenfield discharge/approval is governed by DfI Rivers. Applicant to demonstrate clearly on application form how the proposed discharge rate has been calculated and provide evidence of correspondence with DfI Rivers.

Returning completed forms

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

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

Telephone: 03457 44 00 88
Email: developerservices[AT]niwater[DOT]com

For more information on how NI Water lawfully processes personal data please refer to our Privacy Notice:

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