Foundation Drainage Pumping

If a building design cannot achieve a basement with a gravity connection for the foundation drainage and the property owner chooses to pump the foundation drainage, then the following design requirements are expected to enable pumping:

1. The design of the pumping system is to be done by a qualified professional (Professional Engineer with expertise in drainage and pumping systems);
2. The foundation drainage is required to gravity drain to an inceptor sump prior to gravity draining into the sump which will house the pump;
3. The sump which will house the pump is required to be designed by the Professional Engineer to allow for the storage of some water to enable the operation of the float switches to reduce the risk of a pump short cycling and burning out;
4. The pump system is required to utilize a dual (duplex) pump setup with a primary and backup pump. Both pumps are required to be sized individually to manage designs flows generated by a major rainfall event defined as a 1 in 100-year occurrence;
5. An auto start natural gas generator back-up power supply for the pump system is required to be incorporated into the design, to ensure that in the event of a primary power failure the pumps will continue to operate;
6. To minimize the risk of the backup pump seizing from lack of use, the pumps to be wired to alternate such that they both operate on a regular basis;
7. The pump system design to include an in-house high water level alarm;
8. The pumped discharge pipe is required to discharge into a secondary sump on the property, prior to then flowing by gravity pipe to the inspection chamber (IC) at the property line;
9. Design lot grading must consider the potential of surface flooding during the major rainfall event and ensure that the building and basement wells are protected. The Professional Engineer is to conduct an appropriate assessment at the property frontage to ensure that site grades will minimize risk of surface flooding.

Illustration 1: Typical pump layout on a site plan 

Illustration 2: Typical pump layout with a shallow storm sewer 

Illustration 3: Typical pump layout with a deep storm sewer

Deeper storm sewer connections:

Use this or equivalent arrangement when the storm sewer inspection chamber can be installed deep enough to drain the basement slab by gravity, but the 100 year hydraulic grade line (100 yr hgl) prevents a basement. The primary drainage will be by gravity with the pump system working only when the hgl rises in the storm sewer main. 

The design for the pumping system is required to be submitted with the initial building permit application. It is the responsibility of the property owner and building permit applicant to ensure the appropriate analysis has been completed to determine the appropriate design of the building foundation drainage system prior to submitting the building permit application.

Submit the following items with your building permit application: 

1. An original sealed set of design drawings from a qualified professional (Professional Engineer with expertise in drainage and pumping systems). The design drawings are required to adequately demonstrate:
   • How the foundation drainage and proposed pumping system design substantially complies with the requirements identified in this bulletin, the BC Building Code (BCBC), and the National Plumbing Code of Canada (NPC);
   • The assumptions and determination of the ground water contribution under the design event and how it was applied to the pump and sump volume and sizing. As well, the analysis from desktop reviews and site investigations, including the results of subsurface testing and examination; and
   • Align with Engineers and Geoscientists of British Columbia professional practice guidelines, including Issued for Building Permit Documents.
2. An original sealed letter from the Professional Engineer providing:
   • Assurance that their design, in support of the building permit application, substantially complies with the BC Building Code and other applicable enactments respecting safety; and
   • Commit to undertake field reviews of the work during construction.

Before a building permit is issued

Once the design has been accepted, a Section 219 restrictive covenant will be required to be registered against the property. The restrictive covenant will provide future and current property owners awareness of the pump system and identify the responsibility of the owner for maintenance and repair. A template and instructions for registration will be provided during the application process and must be accepted before the building permit can be issued.

During construction of the building

All inspections outlined under the Building and Plumbing Bylaws will need to be scheduled and accepted prior to the covering of any work. During the inspections related to the piping, sumps, and pumps, field review reports from the Professional Engineer must be submitted in order for the inspection to be accepted.

Before occupancy is granted to the building

The Professional Engineer will be required to submit a letter confirming the following:

1. That they have fulfilled their professional obligations to conduct field reviews for the works that they designed; and
2. That the work installed substantially complies with the design and supporting documentation that they provided in support of the building permit application.