A few of the cities stand out as having permissive codes that eliminate common barriers to ADUs. Vancouver, BC may have the most permissive ADU codes of the 55 cities examined. Vancouver, BC allows a single family property to have 1 attached ADU and 1 detached ADU on each property. That’s right – you can have a basement unit AND a detached backyard ADU. The detached ADUs, however, have a 500 sqft size limit, which is lower than the 800 sq ft limit common in most other cities. They also don’t have any requirements for parking, owner occupancy or design, which are all seen as a barriers to development in most cities that allow ADUs. Also, check out Richmond and Victoria BC.
Portland, Oregon does not require owner occupancy or parking and has fairly generous size limits. These rules, combined with a $12,000 system development charge waiver has helped support a rapid increase in the number of ADUs in Portland. Prior to the 2010 waiver, Portland permitted an average of 25 ADU per year. In 2012, the permit activity rose to 140 permitted ADUs.
Another Oregon city to highlight is Ashland. They don’t have owner occupancy or design requirements and also allow ADU up to 1,000 sqft. That’s huge!
Something to consider – should cities follow the BC pathway to curb the size of detached ADUs to 500 sqft and allow properties to have BOTH a detached ADU and an attached ADU on one property?