Appendix D: Calculating maximum build-out density under SSMUH zoning
A guide for municipalities to calculate the potential total increase in housing units resulting from new zoning amendments required by provincial legislation.
Appendix D: Calculating maximum build-out density under SSMUH zoning
Following the geospatial analysis undertaken earlier to identify the lots that must undergo zoning amendments in response to SSMUH legislation, local governments should know, or be able to easily query:
- the number of lots that must be permitted to have at least one secondary suite or one ADU;
- the number of lots that will be permitted at least three housing units;
- the number of lots that will be permitted at least four housing units; and
- the number of lots that will be permitted at least six housing units.
In all the above categories, determining the maximum potential build-out is simply a function of multiplying the number of lots in each category by the number of dwelling units permitted in that category, and then totaling the numbers for all categories.
For example, if there are 577 properties with zoning that must be amended to permit either one secondary suite or one ADU, then the maximum build-out of this zoning category is 1,154 (577 x 2; since the zone will allow for one principal dwelling unit plus one smaller dwelling unit). If a secondary suite and ADU is permitted on these 577 properties, then the maximum build-out density is 1,731 (577 x 3).
If there are 262 properties whose zoning must be amended to permit at least four dwelling units, then the ultimate build-out of this zoning category is 1,048.
Determining the maximum net increase in units requires some effort to align the unit calculations from the maximum build-out to counts of existing units from either the Statistics Canada Census or BC Assessment. Approaches using both data sets are outlined below.
1. Method 1 - BC Assessment approach
a) BC Assessment produces a standard yearly digital dataset called the BC Building Information Report. This report is available to all local and regional governments from BC Assessment free of charge.
b) This report can be structured to indicate the number of units at the parcel scale. This can be achieved by identifying all parcels with single detached actual use codes and assigning them a value of 1 and all parcels with secondary suite actual use codes and assigning them a value of 2.
c) Net increase in units can be calculated by using the selections and totals generated in the section above less the values determined in step b above. These increases can be used at the disaggregate level or summarized to the municipal level as appropriate.
2. Method 2 - Census data approach
While lacking in spatial specificity, this technique can be used to rapidly determine the net increase in units against a 2021 baseline through the steps below.
a) An individual jurisdiction's Census Profile can be accessed through Statistics Canada. This profile contains the number of units by jurisdiction.
b) Total increases in units can be determined by deducting the Census value from the totals determined in the maximum build out density.