Rainwater management on private property (drainage)

All new development applications for Part 3 (complex) buildings (excluding residential buildings with up to 8 dwelling units) must demonstrate compliance with the Building By-law rainwater management requirements at the plumbing permit application stage. No rainwater management documentation is required at the rezoning or development permit application stages. Review the requirements in the Building By-law (Book II, Division B, Article 2.4.2.5.) External website, opens in new tab 

Information icon Effective July 1, 2025, these requirements will be referred to as the "engineered pathway" for compliance, and the applicable building types will change. Review the applicability section for details.

Alterations to existing buildings are exempt from the new Building By-law rainwater management requirements. Review the exemption in Building By-law Book I, Division B, Sentence 11.2.1.1.(2) External website, opens in new tab

New rezoning applications may be subject to site-specific rainwater management conditions approved by Council. Review Council decisions for rezoning applications

Information icon New developments in First Shaughnessy have area-specific rainwater management requirements. Review the First Shaughnessy District Schedule requirements (section 4.4) PDF file (250 KB) and design guidelines (section 4) PDF file (7 MB).

For development permits opened* before January 1, 2024, if rainwater management was:

• Required: You may be eligible to transition to the Building By-law rainwater management requirements. Review information on transitioning in-stream applications
• Not required: You will be sheltered from the Building By-law rainwater management requirements that came into effect on January 1, 2024.

A direct-to-building permit application that was opened* before January 1, 2024, will be sheltered from the new Building By-law rainwater management requirements.

Explanatory note

* The date that a permit is "opened" is seen as the "application date" in our online portal. Search for a permit

Water quality standards for discharged storm water can be found in the Sewer and Watercourse By-law (section 3) PDF file (346 KB).

Information icon A new requirement for on-site rainwater management comes into effect for most new single-family homes, duplexes, and multiplexes as of July 1, 2025. Review the upcoming requirements

Grade differences between adjacent lots can create drainage problems. For new homes, surface water flows must be contained and managed by a storm water drainage system on the same property. This can be accomplished with a retaining wall and drain tile system along the elevated areas.

Rainwater collected on pavement or concrete (such as on driveways, parking pads and patios) must not be directed to neighbouring properties, and must be conveyed to the storm sump.

For rainwater infiltration practices, there are minimum setbacks from buildings and neighbouring properties. Review the requirements in the Building By-law Book I, Division B, Article 9.14.5.3 External website, opens in new tab, (Notes) External website, opens in new tab.

References:

• Vancouver Plumbing By-law, Division B, Article 2.4.2.4 External website, opens in new tab
• Vancouver Building By-law, Division B, Section 9.14 External website, opens in new tab

Compliance with the Building By-law rainwater management requirements External website, opens in new tab will be verified at the plumbing permit application stage. 

The plumbing permit application is submitted online and must contain:

• Project Summary form PDF file (148 KB)
• Site schematic showing rainwater management and drainage components (example of a site schematic PDF file (560 KB)). The Project Summary form may be included on the same page as this schematic.
• Design drawings, supporting calculations, and references
• Schedule B from the plumbing registered professional of record and the civil registered professional of record (if not already submitted at the building permit application stage)

For guidance on Schedule B, refer to the Province’s Guide to the Letters of Assurance (section 21.2) External website, opens in new tab.

An operations and maintenance manual must be provided to the owner, but is not required at the plumbing permit application stage.

Effective July 1, 2025, these application requirements will apply to the “engineered pathway.” A plumbing permit application for the “small site pathway” will not require the documentation described above.

Learn more about permit processing times and fees

For development permit applications opened before January 1, 2024

If your project requires a rainwater management plan, you may be eligible to transition to the Building By-law rainwater management requirements External website, opens in new tab. Contact your project coordinator or project facilitator to determine eligibility.

Eligibility will depend on whether or not construction has started and the conditions applied to your project. For eligible projects, the building’s design for rainwater management must meet:

• The more restrictive of the “release rate requirement” of the Building By-law and the terms of the rezoning approval (if applicable) and development permit, and
• The greater of the volumetric “capture requirement” of the Building By-law and the terms of the rezoning approval (if applicable) and development permit.*

Generally, a requirement for a water quality treatment device may not need to be carried forward into construction for projects that transition to the Building By-law rainwater management requirements, but the development must still comply with erosion and sediment control requirements and water quality standards for discharged stormwater (Review reference documents).  

* Certain sites are exempt from the “capture requirement” under the terms of their rezoning approval (if applicable) and development permit. This exemption may be carried forward.

For eligible projects without an issued development permit:

You will need to show compliance with the Building By-law rainwater management requirements at the plumbing permit application stage. No rainwater management documentation will be required for eligible projects at the rezoning or development permit application stages. 

Generally:

• We will deem the appropriate rainwater management conditions to have been met in the “prior-to permit issuance” letter and Referral Report (as applicable), by virtue of compliance with the downstream plumbing permit application process.
• We will remove any holds on a building permit or occupancy permit related to rainwater management and will waive the obligation for a rainwater management legal agreement. 

For eligible projects with an issued development permit, but which have not commenced construction:
        
You will need to submit a (new or revised) plumbing permit application to show compliance with the Building By-law rainwater management requirements. 

Generally, we will remove any holds on a building permit or occupancy permit related to rainwater management.

After the plumbing permit has been issued, you may request to unwind the rainwater management legal agreement. To complete this process, submit a Form C (Release), which you can obtain and have prepared by a notary or lawyer. 

For eligible projects that have started construction:

Projects under the Certified Professional program with staged construction may be eligible to transition to the Building By-law rainwater management requirements External website, opens in new tab, if construction has not progressed beyond excavation and shoring. Eligible projects will need to follow the process described above for projects with an issued development permit.

All other requests to transition to the Building By-law rainwater management requirements will be addressed case-by-case. Questions? Email rainwater@vancouver.ca

The location and depth of the storm sewer connection are determined through the sewer connection permit process. Typically, the depth of cover is 1.52 m for low-density residential development and may be up to 2.4 m for complex buildings. 

In some cases, this may prevent gravity drainage of a detention tank. To accommodate a gravity connection, you can request a deeper storm invert by contacting Sewer Connections staff at eng.swpermits@vancouver.ca. This request may be submitted as early as at the development permit stage. There is no guarantee that a deeper connection can be supported, as local constraints may limit the maximum permissible connection depth.

References:

City of Vancouver Engineering Design Manual (section 5.6.3) PDF file (9.9 MB)

• Building By-law rainwater management requirements External website, opens in new tab
• Sewer and Watercourse By-law PDF file (346 KB)
• Engineering Design Manual (Section 5) PDF file (10 MB)
• Erosion and sediment control, large lot developments (more than 1,000 m²) PDF file (241 KB)
• Erosion and sediment control, small lot developments (less than 1,000 m²) PDF file (664 KB)

Effective July 1, 2025, most new buildings must provide on-site rainwater management. The requirements are not retroactive. There are 2 compliance pathways based on site area and floor space ratio (FSR):

• For projects up to 1.0 FSR on sites up to 1,000 m² (about 10,760 sq ft) - follow the small site pathway
• For projects exceeding 1.0 FSR, sites greater than 1,000 m², or both - follow the engineered pathway

Floor space ratio (FSR) is defined by the Zoning and Development By-law, and the value used is after applicable exclusions. All housing options in the R1-1 zone PDF file (1.4 MB) are within 1.0 FSR.

Exempt from these requirements are:

• Laneway houses and infill added to a site with an existing building, where the site area is no greater than 1,000 m². Review the Zoning and Development By-law definitions PDF file (912 KB). (Note: where the site area is greater than 1,000 m², the engineered pathway applies.)
• Accessory buildings - Review the Zoning and Development By-law definition PDF file (912 KB)
• Float homes and marinas - Review the Building By-law definitions External website, opens in new tab
• Retaining structures
• Temporary buildings - Review the Building By-law Book I, Division C, Subsection 1.6.8. External website, opens in new tab
• Alterations to existing buildings - Review the Building By-law Book I, Division B, Sentence 11.2.1.1.(2). External website, opens in new tab

Additionally, certain development permits opened* before January 1, 2025, will be sheltered from the new Building By-law rainwater management requirements, if a building permit is opened* prior to January 1, 2026. This includes:

• Buildings to which Part 9 applies. Review the Building By-law Book I, Division A, Sentence 1.3.3.3.(1) External website, opens in new tab
• Buildings to which Part 3 applies and are used exclusively for residential occupancy, with up to 8 principal dwelling units. Review the Building By-law Book I, Division A, Sentence 1.3.3.2.(1). External website, opens in new tab

Information icon Certain projects in-stream before January 1, 2025 may be subject to site-specific rainwater management requirements, such as within the Cambie Corridor or Broadway Plan areas. These may be eligible to transition to the simplified Building By-law requirements upon request. Review information on transitioning in-stream applications

Explanatory note

* The date that a permit is "opened" is seen as the "application date" in our online portal. Search for a permit

Other requirements may be applicable:

• New rezoning applications may be subject to site-specific rainwater management conditions approved by Council. Review Council decisions for rezoning applications
• New developments in First Shaughnessy have area-specific rainwater management requirements. Review the First Shaughnessy District Schedule requirements (section 4.4) PDF file (250 KB) and design guidelines (section 4) PDF file (7 MB).

Effective July 1, 2025, most new projects up to 1.0 FSR and on sites up to 1,000 m² are subject to the rainwater management requirements of the “small site pathway.” Review the applicability section for exclusions.

This requires the installation of a rainwater detention tank based on site area:

Suppliers providing rainwater detention tanks PDF file (88 KB)

The “minimum active storage capacity” excludes the volume below the orifice and above the emergency overflow. It is not the same as the overall volume of the detention tank.

The detention tank must be able to support the design depth of cover and surface loads.

Review the draft requirements in the Council Report

Effective July 1, 2025, most new projects greater than 1.0 FSR, on sites greater than 1,000 m², or both, are subject to the rainwater management requirements of the “engineered pathway.” Review the applicability section for exclusions.

These are the same requirements that are presently applicable to most new Part 3 buildings. Review the requirements in the Building By-law (Book II, Division B, Article 2.4.2.5.) External website, opens in new tab

Alongside coordinated sewer system upgrades, private property rainwater management will enable housing development to proceed by helping to relieve sewer system capacity constraints. It will also help to meet regulatory obligations.

References:

• Combined sewer overflows in the city of Vancouver
• Basin characterization maps PDF file (8.1 MB) in the city of Vancouver
• Real-time sewer overflow map External website, opens in new tab from Metro Vancouver

The preferred rainwater management tools are those that integrate natural systems, reduce the volume of rainwater entering the sewer system, and control the rate of rainwater release from a site:

• Landscape-based solutions can allow rainwater to soak into the ground or return to the atmosphere. Learn more about drainage requirements for low-density development
• Non-potable water systems can use rainwater instead of drinking water for applications like toilet flushing. They can also help to reduce water and sewer utility bills. Learn more about non-potable water system requirements
• Vegetated roofs (green roofs) can absorb rainwater, allow some to return to the atmosphere, and slow down runoff into the sewer system. Information icon New standards for vegetated roof installations came into effect on July 1, 2024. 
  • Reference documents:
    • Vancouver Building By-law, Division A, Section 1.4 External website, opens in new tab, (Notes) External website, opens in new tab
    • Vancouver Building By-law, Division B, Article 3.1.14.4 External website, opens in new tab
    • Vancouver Building By-law, Division B, Article 5.2.2.2 External website, opens in new tab, (Notes) External website, opens in new tab
    • Vancouver Building By-law, Division B, Section 5.6 External website, opens in new tab, (Notes) External website, opens in new tab

Learn more about green rainwater infrastructure

To reduce the volume of sanitary sewage entering the sewer system (and to reduce the use of drinking water), we have water efficiency requirements PDF file (251 KB) for plumbing fixtures and mechanical equipment. 

As of March 2025, 166 new developments with issued building permits will meet the on-site rainwater management requirements. In total these will:

• Manage 57 hectares (for comparison, Queen Elizabeth Park is 53 hectares)
• Reduce peak rainwater runoff by about 6,250 litres per second (for comparison, review Capilano and Seymour River External website, opens in new tab flow rates)
• Add 63 new green roofs totalling 3.4 hectares (for comparison, Nanaimo Park is 2.9 hectares)
• Add 5 new building-scale rainwater harvesting (non-potable) water systems for flushing toilets and other uses (Review map of existing non-potable water systems)

Additionally, many of these developments will provide public green infrastructure like trees, bioretention curb bulges, and infiltration trenches along the right-of-way. Learn more about public green infrastructure

Council approved streamlined rainwater management requirements PDF file (696 KB) in July 2023. This immediately simplified the:

• Green Buildings Policy for Rezonings PDF file (246 KB) and associated Bulletin PDF file (121 KB)
• Rezoning Policy for Sustainable Large Developments PDF file (1.1 MB) and associated Bulletin PDF file (427 KB)

Additional changes took effect on January 1, 2024:

• Zoning and Development By-law: rainwater management requirements were removed from sections 4.3.4, 4.3.5, and 4.3.6 and the Rainwater Management Bulletin is no longer being used.
• Vancouver Building By-law External website, opens in new tab

A memorandum about the transition process for in-stream applications PDF file (375 KB) was sent to City Council on November 30, 2023. A memorandum about expanding rainwater management requirements PDF file (187 KB) was sent to City Council on June 11, 2024.

New requirements for vegetated roof assemblies (green roofs) took effect on July 1, 2024 in the Vancouver Building By-law. Review the Council Report PDF file (431 KB)

Council approved on-site rainwater management requirements for most new buildings, which will take effect on July 1, 2025. Review the Council Report from November 12, 2024 PDF file (403 KB)

Find Council decisions