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Background Information

In areas where water supply is constrained, composting toilets can be a cost-effective, environmentally friendly addition to conventional on-site septic systems. The use of composting toilets in BC is supported by the Manual of Composting Toilet and Greywater Practice, which was introduced in 2016. The Manual provides a comprehensive set of provisions that support the design, installation and maintenance of composting toilet-based sewerage systems, and aligns with the Sewerage System Regulation (SSR), Environmental Management Act, Municipal Wastewater Regulation and BC Building Code. A composting toilet system can now be filed as part of a SSR filing with the local health authority.

The Manual introduces new standards for the management of composting toilet residual organic matter, and identifies three options to manage composting toilet residuals: off-site discharge; on-site burial; and on-site surface application. Monitoring and processing requirements specified in the Manual now make it more challenging for homeowners with composting toilets to discharge organic residuals on-site. 

Further information on composting toilets in BC can be found in the Composting Toilet and Greywater Guidelines document from the Canadian Onsite Technical Resource Association.

Frequently Asked Questions

Below are some questions and answers about composting toilets. If you have any further questions please email us.

What are the benefits of composting toilets?
  • Saving water (conventional toilets account for over 25% of household indoor water use)
  • Cutting down on septic system construction and pump-out costs
  • Reducing stress on older septic systems
  • Providing alternative options for sites where a full septic system may be difficult to install
  • Producing material that, with proper treatment, can be turned into safe usable compost
Are composting toilets legal?

Yes. In 2016, the BC Ministry of Health established composting toilets and greywater systems as a sewerage system option under the Sewerage System Regulation.

The Ministry of Health provides the Manual of Composting Toilet and Greywater Practice as a source of standard practice for design, construction and maintenance of composting toilet and greywater sewerage systems. This manual is in addition to the Sewerage System Standard Practice Manual.

Can an average person set up, use, and manage a composting toilet?

The Sewerage System Regulation (SSR) requires that systems are constructed by or under the supervision of an Authorized Person (AP). An AP is either a Registered Onsite Wastewater Practitioner (ROWP) or qualified professional. The AP is responsible for the planning, installation and maintenance of the composting toilet system according to the Manual of Composting Toilet and Greywater Practice requirements, and for filing documentation with the Health Authority. The composting toilet system owner is responsible for operating and managing the system, which includes engaging an AP to either undertake or supervise maintenance.

Construction of a system can start once the AP files a record of sewerage system with the local Health Authority. The filing is based on site and soil evaluation, and evaluation of the proposed use. The filing includes design and specification details of the system components.

During construction, the homeowner may work with or under the supervision of an AP, or an AP can build the system. After construction is complete, the AP will file a letter of certification (with maintenance plan and other details) with the Health Authority.

The SSR requires that systems be maintained by or under the supervision of an AP. After the system is complete, the maintenance plan will define roles and responsibilities, including what is considered operation (by the homeowner) and what is considered maintenance (by the AP or by the homeowner with supervision by the AP), and for tasks where supervision is needed, what form that will take. Typical operational tasks might include management of the toilet pedestal and processor, together with record keeping, with periodic review by the AP.

Are composting toilets hygienic and safe?

Yes, composting toilets are hygenic and safe when the standards in the Manual of Composting Toilet and Greywater Practice are followed. This includes requirements for the safe treatment and disposal of residuals.

What are residuals?

Residuals are the solid materials that are the end product of the composting toilet. Although these may sometimes look like finished compost, they are not necessarily safe for unrestricted use.

Are there strict requirements for treating and disposing of residuals?

Yes. Residuals treatment and disposal needs to be done carefully to protect public and environmental health. The Manual of Composting Toilet and Greywater Practice details the requirements, including testing, record-keeping, and involvement by an Authorized Person.

What are options for residuals treatment and disposal?

The Manual of Composting Toilet and Greywater Practice establishes two options for managing residuals:

  1. Transporting them to an approved off-site facility; and
  2. Dealing with them on-site.

One option for off-site discharge is to transport residuals to an approved composting facility which is permitted to receive this type of waste. Composting facilities in BC are regulated by the Organic Matter Recycling Regulation. Odour control and protection of groundwater are key considerations in operation of a composting facility for residuals management. The facility would convert untreated or partially treated residuals into an approved compost product which is safe for use as a soil amendment.

On-site treatment and discharge by burial or other approved methods is possible, under supervision by an Authorized Person. This requires suitable soils and significantly more effort in terms of process and monitoring than off-site options.

If I have a composting toilet, do I still need a system to treat other household wastewater?

Yes. If left untreated, this wastewater can smell bad and be harmful to people and the environment. You are required by law to treat and discharge the effluent in accordance with standard practice. Systems for treating household wastewater can be simpler and less expensive when composting toilets are used instead of flush toilets.

Is the Hornby Island Composting Toilet Study complete?

Yes, the Hornby Island Composting Toilet study is complete, and was presented to the CVRD Electoral Area Services Committee in September 2020 (link). The recommendation in the report to further investigate the option of collecting residuals on Hornby Island for processing at the Comox Valley Sewerage Service's biosolids composting facility was accepted by the EASC, with a follow up report presented to the EASC in November 2021 (link).