Composting Toilets

Aquarian Systems was a member of the technical team assisting in the creation of British Columbia’s Manual of Compost Toilets and Greywater Practice (MCTGWP) in 2016.

The Manual specifies standards and guidelines for the design, installation, monitoring, and maintenance of composting toilets and greywater systems. It is an extension of the B.C. Sewerage System Regulation and as such cross references to the Standard Practice Manual Version 3 for onsite wastewater management practice.

In B.C. an Authorized Person (AP) such as a Registered Onsite Wastewater Practitioner (ROWP) or a wastewater engineer is authorized to plan and construct, or oversee the construction and maintenance, of a compost toilet or greywater system. The AP must file the documentation for the compost toilet and/or greywater system with the local environmental health office. A list of AP’s in British Columbia can be found on the ASTTBC web site.

B.C. Building and Plumbing Code and Composting Toilets.

The Manual outlines the guidelines for building or plumbing inspectors to allow for composting toilets as an alternative to that specified by the Building Code. See appendix D-4.


In the Manual of Compost Toilet and Greywater Practice, the standards and guidelines for treating/using greywater is separated into its various sources, such as, kitchen sink, compost toilet leachate, bath, and laundry. Options are presented for combined collection and treatment or source separating for purposes of landscape irrigation or fertigation (blending urine with light greywater), or mulch basins around the base of trees, (fruit, nut, or ornamental). The Manual does not allow for irrigation of food crops other than those that are woody stemmed.

Some options for greywater treatment/use are:

  • Planter beds (piloted in B.C. by Aquarian Systems, Ron McMurtrie & Associates Consulting Engineers, and GreenHouse Organic Sewage Treatment Society)
  • Constructed wetlandsEvapotranspiration gardens
  • Mulch basins
  • Sub-surface drip irrigation (non-food crops)
  • Reuse for toilet flushing, see page 123 of the Manual

Learn More:

B.C. Manual of Composting Toilets and Greywater Practice

The Humanure Handbook

MCTGP_WCOWMA_Workshop_2017_R0D2 (Presentation on Composting and Wastewater Management)

Zerowaste Report

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