Legislation-

In July of 2003, a new law went into effect- Assembly Bill 1866.  This has come to be known more commonly as the "Granny Unit" or "Granny Flat" Law. The purpose of this new law was to help address the well-documented affordable housing crisis here in the State of California. In a state with some of the most cumbersome, multi-layered, and convoluted building permit processes in the Union, the idea was to try and streamline the permitting of smaller secondary dwelling units, to increase the housing density of already established areas, provide affordable places for people that may not be able to afford to own their own home in California (an increasingly large percentage of working people and families), to allow for families to house their elderly relatives at home, and to also help prevent further urban sprawl.

Each City or County May be Different-

This bill required all City and County jurisdictions to implement streamlined building permit processes for these kinds of units on properties where they may already be a single family dwelling. Under most current zoning ordinances at the time, these types of units would not be possible on the most common sizes of residential lots. But each jurisdiction was also allowed to customize its own ordinance as long as it met certain guidelines. At the time of this writing, there has already been a lot of controversy and backlash about this bill and some jurisdictions have suspended approval of these types of projects so check the status of this with your local Planning and/or Building Department. See the City and County Links Page for your jurisdiction.

Some Limitations-

Typically, this type of project will only be allowed on a property that you own and occupy. If it is a rental property, you may not be allowed the secondary unit. There may also be certain sections of your City or County where they have been determined to be incompatible in those areas for any of several reasons. Again, check with your local departments to see if your property qualifies.

The property may also have to

Usually, the style of the secondary unit will need to be compatible with the existing style of your house. Basically, they don�t want two completely different looking units on the same property.

You may also be limited to how much of your parcel may be covered by the two structures. "Coverage" sometimes includes garages, carports, decks, etc., sometimes it doesn�t. Again, check with your local departments.

Parking-

If you find that your local jurisdiction is still allowing and/or approving the new types of units, and you have determined the maximum square footage that will be allowed for the secondary unit, the next most important issue will typically by parking. You will have to provide a minimum of one additional "off street" (meaning on your property) parking space for the secondary unit, and may have to provide one space per bedroom of the new secondary unit, in addition to meeting the parking requirements for the primary dwelling unit.

Sometimes this parking can be in tandem (one possibly blocking the other on a long driveway, etc.), sometimes not, and sometimes it will be allowed within the front setback, and sometimes not. Sometimes the parking will be required to be "covered" (either in a closed garage or under a carport roof of some kind), or sometimes it may be uncovered. In the case of a garage or carport that is specifically part of the new secondary unit, that structure may be limited to 50% of the size of the secondary unit. Not to beat a dead horse here, but always confirm everything with your local departments.

Design & Permits-

Once you have determined that your parcel is eligible for a secondary unit, then the permitting process is much like that for other similar projects like new homes, or for addition/remodel projects, so look into those articles on the home page.

 The design of the unit could also start with some of the basic rules of thumb that I use in all my designs.

I offer a low cost feasibility analysis to confirm whether or not your existing parcel qualifies for a secondary unit and some basic guidelines as to how you can go about designing it.