From the article at: Novato Accessory Dwelling Permit pdf

When Required

A permit is required for an accessory dwelling (second unit) on a parcel zoned for single-family residential use. The City allows accessory dwellings to encourage the provision of small, affordable rental units. The City regulates accessory dwellings by established standards in order to minimize their impact on the
neighborhoods.

An accessory dwelling may be requested to enable the construction of a new unit or to legalize a previously constructed unit. If an accessory dwelling permit is approved for a previously constructed unit, a building permit will also be necessary in order to legalize the construction. Additional work is often necessary to bring the unit into conformance with building codes. Some utility agencies charge “hook-up” fees to serve an accessory dwelling.

Pre-Application

You should familiarize yourself with the standards for accessory dwellings prior to making your application. A summary of these standards is listed below. Chapter 19.34, “Accessory Dwellings,” of the Novato Municipal Code has the specific standards. Accessory dwellings must conform to all other City regulations such as building codes, security requirements, grading restrictions, etc. YOU SHOULD ALSO CHECK TO SEE IF ACCESSORY DWELLINGS ARE PROHIBITED IN ANY CC&R’S (CONDITIONS, COVENANTS, AND RESTRICTIONS) FOR YOUR SUBDIVISION.

Standards for Accessory Dwellings:

1. Accessory dwellings are permitted in the RR (Rural Residential), R1 (Single-Family Residential), R4, R5, R10 and R20 (Medium and High Density Multi-Family Residential) zoning districts.
2. The owner of the parcel must occupy as a principal residence, either the primary residence or the accessory dwelling.
3. Only one accessory dwelling is allowed on a legal lot.
4. The accessory dwelling shall be subject to the same requirements as a primary dwelling for setbacks, lot coverage, and height.
5. Three independently accessible parking spaces for the two residences are required, at least one of which must be covered.
6. Both units shall have illuminated house numbers visible from the street.
7. Colors, materials, and design of the accessory dwelling shall incorporate the same or similar architectural features as the primary dwelling or compatible dwellings located on adjacent properties.
8. Additional specific standards, based on the type, ATTACHED or DETACHED accessory dwelling, are listed below:
a. ATTACHED DESIGNS: A type of accessory dwelling in which common exterior structural elements of the existing dwelling, such as a roof and load bearing wall, are integrated into the design and/or extended, without separation, as an addition to the existing dwelling:
1) Maximum accessory dwelling size: 50 percent of primary dwelling heated floor area, not to exceed 750 gross square feet. An additional 50 square feet of floor area may be allowed for each 2,000 square feet of lot size over 10,000 square feet up to a maximum of 1,000 gross square feet of floor area.
2) Minimum accessory dwelling size: 150 gross square feet.
3) A separate exterior entry shall be provided to serve the accessory dwelling. Interior doorways between the existing dwelling and the attached accessory dwelling should be avoided.
b. DETACHED DESIGNS: A type of accessory dwelling which is structurally independent and separated from the existing dwelling.
1) Maximum accessory dwelling size: 60 percent of primary dwelling heated floor area, not to exceed 750 gross square feet. An additional 50 square feet of floor area may be allowed for each 2,000 square feet of lot size over 10,000 square feet up to a maximum of 1,000 gross square feet of floor area.
2) Minimum accessory dwelling size: 150 gross square feet.
3) A minimum setback of 3 feet between the exterior walls of the existing dwelling and the accessory dwelling.

Read the full article at: Novato Accessory Dwelling Permit pdf

Novato Building Division