Shallow buried trenches are used to dispose of treated septic effluent via small diameter pipes under pressure into chambers placed in the upper soil layers. The system makes the effluent more available for plant root uptake & processing by a host of microbial & bacterial life.

Intended Use:

  • Environmentally sensitive areas
  • Sites in close proximity to ground water
  • Small building lots Less permeable soils (e.g., heavy clay)


  • Effluent must be first sufficiently treated to allow it to freely move through piping without risk of clogging
  • Effluent is distributed through a pressurized system of plastic PVC piping(not less than 25mm diameter pipe)
  • Distribution system must maintain a minimum pressure head of 600mm in all points of the distribution network
  • Total length of the distribution piping for shallow buried trenches is not less that 30 metres. The individual trenches are 0.3 – 0.6m in width & 0.3 – 0.95 in depth. Trenches are centered at least 1.6m apart. On-site soil is used as backfill in the trench. At least 300mm of topsoil covers the chamber.
  • Pressurized piping is positioned within the chamber(only pre-approved chamber systems are acceptable). Small diameter holes in the top & bottom of the piping evenly distribute the effluent on the soil surface within the chamber.
  • At the time of assembling this booklet, shallow buried trench systems were only approved in three municipalities in Ontario-Lambton & Essex Counties and in Chatham-Kent. Check with local officials for an update on current acceptance of these systems. Estimated Costs: Dependent on treatment system used, the shallow trench materials & installation costs are consistent or less than other compliance alternatives.