Code of Practice for Domestic Waste Water Treatment Systems.

The Code of Practice establishes an overall framework of best practice in relation to the development of domestic waste water treatment systems, in unsewered rural areas, for protection of our environment and specifically water quality and human health.

The 2021 Code of Practice for Domestic Waste Water Treatment Systems (Population Equivalent ≤ 10) applies to site assessments and subsequent installations carried out on or after the 7th of June 2021.

The 2009 Code of Practice Wastewater Treatment and Disposal Systems Serving Single Houses (p.e. ≤ 10) may be used for site assessments and subsequent installations commenced before the 7th of June 2021 or where planning permission has been applied for before that date.

The Code of Practice sets out a methodology for site assessment and selection, installation and maintenance of an appropriate domestic waste water treatment system. It includes information on:

  • policy and legal background;
  • waste water characteristics and loadings;
  • how to characterise a site and decide on the type of domestic waste water treatment system;
  • required minimum separation distances, depths of unsaturated soil and/or subsoil above the bedrock and the water table, and percolation values; and
  • design, installation, operation and maintenance.