Is the 1.2 metre sump discharge distance an Ottawa rule or advice?

The 1.2 metre figure is City of Ottawa advice, not a requirement in Ontario's Building Code.

The Building Code addresses sump discharge in clause 7.4.6.3. It requires a union and a check valve in the discharge line, and that the pump discharge to above grade level. It sets no minimum horizontal distance from the foundation for where that water lands.

The City's flooding guidance recommends connecting the sump pump to the storm sewer or, where that is not possible, discharging to the ground at least 1.2 metres from the foundation.

Downspouts are a separate question, covered by ottawaeavestroughs.com.

If a contractor is proposing to run the sump discharge to daylight rather than tie it into the storm lateral, ask them where the outlet will be, how far from the foundation, and how the discharge point will be graded so water moves away from the house. If they are connecting to the storm lateral instead, ask whether a licensed plumber does or signs off the plumbing portion, and who pulls the building permit, since the City requires one for plumbing alterations and additions.

Before agreeing to any discharge arrangement, ask the contractor to show you in writing exactly where the water goes and confirm it will not drain back toward the foundation after the ground settles.