Updated July 2026
Do You Need a Permit for a Septic System in the Cowichan Valley?
The short answer
In British Columbia a septic system is not permitted but filed. Under the Sewerage System Regulation, an Authorized Person — a Registered Onsite Wastewater Practitioner or a Professional — files the design with Island Health before construction and submits a Letter of Certification when the system is complete. Duncan Septic Systems handles this filing across the Cowichan Valley Regional District.
Updated July 2026
A sewerage system filing is the record an Authorized Person lodges with Island Health under the Sewerage System Regulation, replacing the older 'permit' process for most residential onsite systems.
A licensed crew handles the Island Health filing as part of septic system installation.
Filing, not a permit
British Columbia moved away from health-authority septic permits in 2005. Today most residential systems are handled under the Sewerage System Regulation as a filing: an Authorized Person submits the design to Island Health before work begins, then files a Letter of Certification once the system is built and inspected. The system may not legally be used until that certification is filed.
Who can file — ROWP or Professional
Only an Authorized Person may design, install, and file a system. That is either a Registered Onsite Wastewater Practitioner (ROWP), registered with ASTTBC, who handles Type 1 and Type 2 systems, or a Professional such as an engineer, who can handle any system type. A homeowner cannot file their own residential system.
Island Health and the Cowichan Valley Regional District
Island Health is the health authority that receives sewerage filings for Vancouver Island, including the Cowichan Valley. The Cowichan Valley Regional District may add its own requirements — such as covenants, watershed protection near Shawnigan Lake, or building-permit coordination — so a specific property is confirmed at the assessment.
Maintenance is part of the rules
For Type 2 and Type 3 systems, the regulation requires an ongoing maintenance plan and regular servicing by a qualified person. Keeping to that plan is both a legal requirement and the best way to protect the system.
| System / situation | Who handles it | What's filed with Island Health |
|---|---|---|
| Type 1 (tank + gravity field) | ROWP or Professional | Design filed before build + Letter of Certification after |
| Type 2 (treatment system) | ROWP or Professional | Design + maintenance plan filed; Letter of Certification after |
| Type 3 (tertiary, sensitive sites) | Professional | Design + maintenance plan filed; Letter of Certification after |
How the filing works with your installer
- 1
Assessment & soil evaluation — The Authorized Person evaluates soil and site to determine the system type the property needs.
- 2
Design filed with Island Health — The system is designed and filed with Island Health before any construction begins.
- 3
Letter of Certification — Once built and checked, a Letter of Certification is filed, making the system legal to use.
For pricing, see the septic cost guide. Duncan Septic Systems serves Duncan and Shawnigan Lake.
Not sure what your property needs? Request a free assessment and Duncan Septic Systems will confirm the system type and handle the Island Health filing.