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OBC DIVISION B · PART 9 · SECTION 9.14 — DRAINAGE

What are the weeping tile requirements for house foundations in Ontario?

Foundation drains (weeping tile) of at least 100 mm (4 in.) diameter must be laid around the exterior of the footings, with the top of the pipe below the basement floor level, and covered with at least 150 mm (6 in.) of crushed stone or clean granular material.

Code reference
Where a foundation encloses below-grade interior space, drainage must be provided at the footing level, typically drain pipe or tile not less than 100 mm in diameter laid on undisturbed or compacted soil around the exterior of the foundation, with the pipe top below the underside of the floor slab and covered by not less than 150 mm of crushed stone or other coarse, clean granular material.
OBC Division B, Subsection 9.14.3.

Paraphrased for clarity — open this provision in the BUILDAiD Library for the exact wording.

What this means in practice

Weeping tile is the workhorse of Ontario basement dryness: it relieves water at the footing before hydrostatic pressure can build, which is also why plain dampproofing is usually acceptable instead of waterproofing. Common defects include tile laid above slab level, crushed pipe from backfilling, silt-clogged runs without filter protection, and missing granular cover. The drain must connect to an approved discharge point under 9.14.5., and many municipalities now require sump discharge rather than storm sewer connection.

Plain language

A perforated pipe runs around the outside of your footings, buried in at least 150 mm of gravel, sitting lower than your basement floor. It quietly collects groundwater and carries it away so your basement stays dry.

Related questions

Where must foundation drains and weeping tile discharge in Ontario?What are the surface grading requirements around a house in Ontario?

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This page is provided for general information. Building code requirements depend on your specific project, occupancy and municipality, and code editions change. Always verify requirements against the current Ontario Building Code and confirm with your local building department.