Why is capital cost allowance (CCA) on personal rental properties not calculated for my personal tax?

CCA depreciation/amortization of personal rental properties

It is not advisable to claim a capital cost allowance on rental property as it reduces the actual value of the property. This creates the potential for a large capital gain on a potential future sale. It is viewed as a small amount of savings each year on an appreciating asset, but would result on a larger tax bill if the property was sold as a result of recapture and capital gain. 

If you acquire depreciable property, such as furniture or equipment for the property, you cannot deduct the cost of said property when you calculate your net rental income for the year. However, since these properties may wear out or become obsolete over time, you can deduct their cost over a period of several years. 

You cannot use CCA to create or increase a rental loss. Your CCA claim will be limited to the amount of rental income you have before claiming CCA.

If, before claiming CCA, you already have a rental loss where your rental expenses exceed your rental income, no CCA can be claimed.

The amount of CCA you can claim and their rates are determined by the CRA.