If you are a non-resident of Canada and earn rental income from Canadian real property (land and building), you are required to remit 25% of your gross rental income to the Canada Revenue Agency by certain due date or face up to 15% in penalties and interest.
This is also true for non-residents who sell Canadian property, regardless of whether if was used to generate rental income or solely for vacation purposes.
The truth however, is that all rental and vacation properties have other costs associated with them and simply paying 25% tax on gross rental income or the sales price can be substantial and is often unnecessary.