When does Ontario's Building Code require a sump pump?

Ontario's Building Code requires an automatic sump pump where gravity drainage from the foundation drain is not practical (clause 9.14.5.2). The Code gives no checklist for "not practical", so ask the contractor to explain in writing why gravity drainage will or will not work at your house.

What the Code sets out

The sump pit itself must be at least 750 mm deep and at least 0.25 m² in area, with a cover that resists removal by children and is airtight. Where a pump is required, it must operate automatically. The discharge must include a union and a check valve in that order in the direction of flow, and the water is pumped to above grade level; or the connection includes a union, a check valve and a shut-off valve (clause 7.4.6.3).

Foundation drainage is required at the bottom of every foundation wall that encloses the building interior, unless it can be shown to be unnecessary (clause 9.14.2.1). The drain tile or pipe must be at least 100 mm in diameter, laid so its top sits below the bottom of the floor slab, and surrounded on the top and sides by at least 150 mm of crushed stone or other clean coarse granular material (clause 9.14.3.3). That drainage has to go somewhere: to a sewer, a drainage ditch or a dry well (clause 9.14.5.1). When none of those outlets is reachable by gravity, the pump is what makes the system work.

The City of Ottawa requires a building permit to install a sump pit and pump, and the permit application must include floor plans and the device's location, type, make and model. Because a pump connects to plumbing, ask whether a licensed plumber does or signs off the plumbing portion.

The City's protective plumbing rebate lists sump pumps with battery backup; check ottawa.ca for the current terms, since the City lists the program as under review.

A contractor looking at your basement can tell you whether gravity drainage to an available outlet is feasible, or whether a pump is the only way to move the water. That is the site-specific call the Code leaves to the person on the ground.

Before you agree to anything, ask the contractor to show you on a sketch exactly where the discharge line runs and where it outlets, so you know the water is going somewhere the Code and the City both accept.