Drainage Requirements for Planning Applications

For your planning application to be successful, it must meet the requirements of the Dublin City Council Drainage Division, which are outlined below.

Submissions that do not adequately address these requirements will not be granted approval.

Manholes & Basement Drainage

  • All manholes to be numbered and manhole schedule to be provided on the drainage drawing specifying cover and invert levels.
  • Outfall manholes, in general, shall be 1.2 metres to 1.5 metres deep.
  • All internal basement drainage must be pumped to ground level before being discharged by gravity from the site to the public foul sewer.
  • Outfall manholes must be kept within the final site boundary.
  • Outfall manholes are to be constructed in accordance with the Greater Dublin Regional Code of Practice for Drainage Works. This shall be indicated on the drawing.

Public Sewers

  • No structure shall be constructed over the line of a public sewer.
  • A minimum clearance distance of 3 metres shall be maintained between the edge of public sewers and all structures on site, including boundary walls and attenuation tanks. This distance shall be agreed with Dublin City Council Drainage Division.
  • Are there public sewers on or within 5 metres of the site? If so, these should be clearly shown on the drainage drawings submitted.

Flood Risk Assessment

An appropriate flood risk assessment should be carried out for the development, this should refer to the Greater Dublin Strategic Drainage Study and OPW flood maps.


  • All new developments shall incorporate Sustainable Drainage Systems (see http://www.irishsuds.com for guidance). Full details of these to be provided in the report and shown on the drawing.
  • In general, surface-water discharge should be limited to 2l/s/hectare for both greenfield sites and sites undergoing redevelopment. Details of flow control device to be indicated on the drawing.
  • Attenuation to be provided for a 1/100-year storm, assuming a maximum discharge rate of 2l/s/hectare. Calculations to be provided with submission.

Private Drain Connections

  • In exceptional circumstances a connection to a private drain will be considered.
  • Where a connection is proposed to a private drain, the developer must submit a letter from the architect stating that permission has been granted from all owners of the private drain for such a connections.
  • Where a connection is proposed to a private drain, the developer must comply with the relevant building regulations.

Standard Requirements

  • Attenuation tanks are not permitted under pavements or roadways.
  • All pipes to be constructed in pavements and roadways (both inside and outside the site) must be of minimum diameter 225mm and made of concrete or clayware. Please refer to Section 11 of the Greater Dublin Regional Code of Practice for Drainage Works and National Road Authority specifications.
  • Where the development consists of a number of separate apartment/office blocks, the collector manhole from each block should be constructed as a standard outfall manhole inside the block boundary.
  • A grease trap shall be installed on the waste outlet from sinks of all commercial kitchens.
  • If the development has a car park, has an appropriate petrol interceptor been installed? Please refer to Section 20 of the Greater Dublin Regional Code of Practice for Drainage Works.


For developments greater than 50 dwellings or 125 PE analysis should be carried out to show that the local network has the capacity to facilitate the proposed flows. Details of the GDSDS 2031 System Performance Assessment should be referenced in this analysis. Where there is not adequate capacity, details of the required upgrade works to the local network to facilitate the development should be submitted for approval.

SuDS Property Level Guide
DCC - SuDS D&E Guide (2021)
DCC - Green & Blue Roof Guide (2021)
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