Skip to main content

Accessory Dwelling Units

Definitions

Accessory Dwelling Unit or ADU – An additional residential dwelling unit on a single-family or multi-family residentially zoned property. An ADU can be an attached or detached dwelling unit, providing independent living facilities for one or more persons that has a full, separate kitchen, separate bathroom and separate entrance. ADUs are sometimes known as an “in-law unit,” “second unit,” or “cottage.”

Junior ADU or JADU – A subcategory of smaller ADUs that are contained entirely within a single-family residence. A JADU cannot be more than 500 square feet in size, and it must have its own cooking facilities and separate entrance. Only one JADU can exist on a residential lot, and the property owner must live in the JADU or the remaining structure of the single-family residence.

Connection Fee – A one-time fee for the use, or additional use, of the public sewer that helps cover the capital costs of the public sewer system. See Sewer Connections and Permits for more details and costs.

Regulations

ADUs are regulated by both State law (primarily Gov. Code, § 66310-66342) and local law.  For properties located within the boundaries of the Novato Sanitary District, the land use authority is either the City of Novato or Marin County.  District regulations for wastewater and solid waste also apply.

A property owner will need to obtain a permit from the District and may need to pay a Connection Fee before an ADU can be connected to the public sewer system.  This permit is different from, and in addition to, any permit required by the County or City.

Permit

Every ADU and JADU within the District must have a permit in order to be connected to the public sewer.  To obtain a permit, a property owner must submit a Sewer Permit Application and pay an Administrative/Permit fee.  An additional Wye charge may also be due, if applicable.  The District will also inspect any additions or modifications of the side sewer (lateral) or main.

For help with your permit application visit Novato Permit Connections. 

Connection Fee

State Law Allows Connection Fees

State law tightly regulates the fees that may be charged for development.  The District does charge fees when it performs certain tasks for private development.  These fees subsidize—but do not fully cover—the costs incurred by the District when reviewing and inspecting new development projects that will be connected to the public sewer system.

The District also charges a Connection Fee, which covers some of the costs of the added burden on the public sewer system resulting from the new development.  Generally, a Connection Fee is required any time a new or expanded use is connected to the public sewer.

State law also regulates the types and amounts of fees that may be charged for the development of ADUs.  Some fees, such as “impact fees,” may not be charged for ADUs.  Other fees, such as Connections Fees, must be calculated proportionally.  Note: The ADU Law expressly provides that connections fees are not “impacts fees” and may be charged for any size ADU except as discussed in the Fee Exemptions section, below.  (See Gov. Code, § 66324, subd. (c)(2).)  The two most common categories of ADUs that pay Connection Fees to the District are manufactured ADUs that are delivered to a property and ADUs constructed within a new structure other than a new single-family dwelling.

Calculating a Connection Fee

The District calculates Connection Fees based on the square footage of the ADU proportional to the maximum size allowable for an ADU, which is 1,200 square feet.  Any structure greater than 1,200 square feet is considered a Single-Family Unit (SFU) (or interchangeably, single-family Equivalent Dwelling Unit or EDU) and will be subject to the full Connection Fee, as established by the District Board of Directors and updated each year.

The Connection Fee for ADUs smaller than 1,200 square feet will be the proportion of the ADU size to 1,200 square feet applied against the amount of the full Connection Fee for 1 SFU.  For example, the Connection Fee for a proposed 600 square foot ADU would be calculated at 600/1200 or 0.5 SFU.

Connection Fee Exemptions

There are only two circumstances in which a Connection Fee will not be required for a new ADU: an ADU constructed within an existing structure and an ADU that is permitted by the applicable land use authority as a JADU.

  1. ADU In Existing Structure

The District will not charge a Connection Fee if the ADU is constructed within an existing structure on the property and meets all of the following requirements:

  • The ADU is within the existing space of a single-family dwelling or accessory structure except for no more than 150 additional square feet for the purpose of accommodating ingress or egress.
  • The ADU has its own separate entrance.
  • The ADU has sufficient side and rear setbacks for fire and safety.

(See Gov. Code, § 66323.)

  1. ADU In New Primary Residence

The District will not charge a separate Connection Fee for an ADU if the ADU is built  with a new single-family dwelling and the ADU is within the proposed single-family dwelling.  A Connection Fee would still be charged for the new single-family dwelling.

  1. JADUs

The District will not charge a Connection Fee if the ADU qualifies as a JADU.  The County and City have adopted ordinances providing for the creation of JADUs, as authorized by the ADU Law.  (See Gov. Code, § 66333; Marin County Code § 22.32.125; Novato Municipal Code § 19.34.031.)  A property owner who obtains the necessary County or City permit for a JADU will not be required to pay a Connection fee.

Sewer Service Charge

With the exception of JADUs, all completed ADUs will be charged an annual sewer service charge.