• Cyburbia is a friendly big tent, where we share our experiences and thoughts about urban planning practice, the built environment, planning adjacent topics, and anything else that comes to mind. No ads, no spam, and it's free. It's easy to join!

Granny flats/secondary suites


The City I work for is contemplating allowing secondary suites (granny flats) in our R1 -- Single Family District. Many people are in support of a greater variety of housing options, including secondary suites because we have next to no affordable housing in this community. However, there are several people concerned about traffic increases, noise, impacts to utilities, etc. I was trying to explain to the Planning Commission last night that there are ways to mitigate many of these concerns through added regulations on secondary suites, and that generally speaking a small percentage of existing houses typically retrofit for the second unit given the chance.

When I was in Davis granny flats were conditional uses in the R1 zone, and I think we maybe had four to five permits a year for a population of around 60,000 people. I don't think that is the widespread proliferation that everyone seems to fear here.

So for those of you that have permits for this type of use, do you have any statistics about the number of permits you issued in the past few years in relation to your single family housing stock? Also, what have been the impacts of allowing granny flats (good and bad)?

As always... thanks so much for all of your help. :)


Cyburbian Emeritus
We allow them as accessory uses in all residential districts. The (poorly written) regs are:

"Any portion of a single family residence, intended to be occupied by a resident(s) related through blood, marriage or adoption to a host residence occupant, being no greater than 800 square feet in size, that has an independent wing or area that is self-supporting in terms of livable needs (i.e. unit includes a kitchen, bath, den and bedroom), but is dependent on utility infrastructure of the primary residence. Access to this wing or area may be obtained via one door to the outside and a second non-lockable door or passage way to the main portion of the host residence. Access is permitted to a garage area having no service door.

All such requests are subject to building, site, and operational plan approval of the Plan Commission following written notice being distributed by the Plan Commission to neighboring property owners within 100 feet of the subject property."

We have allowed them for over 5 years. In that time, less than 2 dozen have been petitioned. We have a bit over 8,000 housing units and a population of approx. 22,000 , and as a percentage of units it's running about 0.001%.

There are no discernable traffic impacts, but again, with so few of them out there, we wouldnt anticipate much. I would not expect the proliferation either.

Last year we amened our codes again to also permit guest houses separate to but accessory to to principal single family uses. They require a conditonal use permit. Those regs are more simply stated:

Guest houses on lots of at least 120,000 sq. ft. provided such structure shall not be rented or leased. Such structure shall be a minimum of 1,200 square feet.

Good luck!


Here are the provisions of our by-law.

The idea of special needs of a person typically precludes an increase in traffic as the residents are not really "drivers". The person living in the unit is either being partiually cared for or is the care giver to the residents of the main household.

We have a grand total of 6 or 7 in our City and they are all legal non conforming uses as they have been here forever.

GARDEN SUITE means a temporary, portable detached dwelling unit, located on a lot containing
an existing single unit dwelling for the use of hosted person(s) with identified special needs.

3.4.5 Any lot with a single unit dwelling may host a Garden Suite for the use of persons with identified special needs provided the following regulations are complied with:
a) an application, supporting information and fee in the amount of $100.00 for the locating of a Garden Suite shall be submitted to the Development Officer;
b) no Garden Suite shall be located on a lot until a permit to do so has been issued by the Development Officer; and
c) a Garden Suite shall be constructed, erected and located in the rear yard of the main dwelling only, to the satisfaction of the Fire Chief, and so as to be readily removable and subject to the following requirements:
i) minimum rear yard for Garden Suite 3.0 metres;
ii) minimum side yard for Garden Suite 2 metres;
iii) maximum height for Garden Suite 6 metres;
iv) maximum floor area for Garden Suite 75 square metres;
v) provision for servicing, including potable water, sewer, storm sewer, lot grading and drainage, parking and access shall be provided for the Garden Suite to the satisfaction of City; and
vi) a signed agreement, registered against the title of the property, between the host (property owner) and the City, including provisions outlining the obligations of the host and the occupants of the Garden Suite, termination of the agreement, removal of the Garden Suite when it is no long required and a restoration plan upon removal.