What are the City of Ottawa stormwater rules I need to follow when repaving my driveway?

When repaving a driveway in Ottawa, you need to comply with the City's stormwater management requirements, lot grading standards, and potentially the zoning bylaw's impervious surface limits. Here is what homeowners should know.

Lot Grading Requirements

The City of Ottawa requires that all residential properties maintain their original lot grading pattern. When your home was built, a lot grading plan was filed that shows how water is supposed to flow across your property — typically from the rear yard to the front, with the driveway draining toward the street. When you repave, you must maintain or improve this drainage pattern. You cannot alter grading in a way that redirects water onto neighbouring properties.

If your original lot grading has been altered (intentionally or through settling), repaving is an opportunity to restore proper drainage. The City's Lot Grading Bylaw (2022-157) requires that the finished grade direct surface water away from all buildings.

Impervious Surface Limits

Ottawa's zoning bylaw limits how much of your front yard can be covered by impervious (hard) surfaces like asphalt, concrete, or standard interlock. In most residential zones, the maximum is 50% of the front yard area. If you are widening your driveway during the repave, ensure you stay within this limit. Permeable pavers or permeable interlock can help you stay compliant while maximizing usable driveway area, as they may qualify for partial exemption.

Stormwater Connection Rules

If your driveway drainage system connects to the municipal storm sewer (via a catch basin or underground pipe), you need a plumbing permit from the City. You cannot connect to the sanitary sewer — this is a serious violation. If you are unsure which sewer your property connects to, the City of Ottawa's GeoOttawa mapping tool shows the storm and sanitary infrastructure on your street.

Downspout Disconnection

Ottawa has a downspout disconnection program that prohibits roof downspouts from connecting to the municipal sewer system. When repaving, ensure your contractor does not accidentally connect or redirect downspout flow into a driveway catch basin that feeds the sanitary sewer.

Sump Pump Discharge

If your sump pump currently discharges onto your driveway, the repaving plan should account for this water flow. The City requires sump pump discharge to be directed to a pervious area (lawn, garden) at least 2 metres from property lines, not onto the municipal sidewalk or road.

Permit Requirements

A standard driveway repave (same footprint, no sewer connection) typically does not require a building permit. However, if you are widening, adding a catch basin connected to the storm sewer, or altering lot grading significantly, permits may be needed. Check with the City's 3-1-1 service or the building permit office.

Use Ottawa Driveways to connect with contractors who handle stormwater compliance as part of every driveway project in the Ottawa area.

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Looking for experienced contractors? The Ottawa Construction Network connects Ottawa homeowners with qualified professionals:

• Justyn Rook Contracting
• RenoMotion Inc.
• ALM Construction & Landscaping Inc.
• Demontigny Carpentry
• ARTEXPRO Tile & Finishes