Accessory Dwelling Units
Accessory Dwelling Units (ADUs) Procedures
ADU – Accessory Dwelling Unit: also known as an in-law unit, second unit, or cottage, is 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.
JADU – Junior ADU, an accessory unit that is no more than 500 square feet in size and contained entirely within a single-family residence.
Entitlement – Maximum amount of water NMWD is committed to supply any individual service. Entitlements are obtained via an FRC.
FRC – Facilities Reserve Charge, the cost to provide capacity to new customers through existing or future water facilities in order to serve new connections. See NMWD Regulation 1 for more details and costs.
Legislation and Code
ADUs are governed by Government Code section 65852.2 and JADUs are governed by Government Code section 65852.22. Four versions of section 65852.2 were enacted by AB 3182 in 2020, one of which became operative on January 1, 2020, and another will by its terms become operative in 2025. Subdivision (f) of section 65852.2 prohibits the District from imposing “capacity charges” (i.e., the FRC) and “connection fees” (as these two terms are defined in Government Code Section 66013) for certain ADUs in certain circumstances. Unfortunately, inconsistencies within subdivision (f) – specifically between subdivisions (f)(2) and (f)(4) and (f)(5) – have led to confusion among many potential applicants for water service trying to determine the circumstances in which capacity charges and connection fees may be imposed on an ADU.
Section 65852.2 contemplates that ADUs can be “attached to” or within an existing or proposed “structure” such as a primary dwelling, including an attached garage, a storage area, or an accessory structure; or in a detached structure separate from the primary dwelling but on the same lot as a primary dwelling. Section 65852.2 authorizes land use agencies (City of Novato or County of Marin) to adopt a zoning ordinance permitting ADUs that do not exceed 50% of the floor area of the primary dwelling (attached) and do not exceed 1,200 square feet (SF) in total floor area (if detached).
North Marin Water District Procedures – No Costs Involved
After approval of an ADU by the local land use agency (City of Novato or County of Marin, as appropriate), section 65852.2 prohibits the District from imposing a capacity charge (i.e., an FRC) or a connection fee (including the cost for a new service lateral and meter) for the types of ADUs listed below unless the applicant has requested a separate service line or meter:
- An ADU within the existing space of a single-family dwelling.
- An ADU within the existing space of an accessory structure (which may include an expansion of not more than 150 square feet beyond the same physical dimensions as the existing accessory structure, provided that the expansion shall be limited to accommodating ingress and egress).
- An ADU within the proposed space of a single-family dwelling.
Therefore, there are no charges for ADUs that meet the criteria above.
North Marin Water District Procedures – Costs Involved
For ADUs other than those described in the bullets above, in accordance with Regulation 1, the District is allowed to require a separate service connection and to impose the FRC and any associated new connection fees on the ADU, although subdivision (f)(5) restricts the amount of the connection fee or capacity charge that can be imposed in two respects: 1) the fee or charge must “be proportionate to the burden of the proposed accessory dwelling unit, based upon either its square feet or the number of its drainage fixture unit (DFU) values, as defined in the Uniform Plumbing Code adopted and published by the International Association of Plumbing and Mechanical Officials, upon the water or sewer system”; and 2) The fee or charge must “not exceed the reasonable cost of providing this service.” These requirements are codified in District Regulation 1.
Consistent with section 65852.2, current District regulations, specifically District Regulation No. 1, there are costs involved for an applicant seeking service from the District for:
- An ADU that is not within the existing space of a single-family dwelling, the proposed space of a new single-family dwelling, or the existing space of an accessory structure (allowing for an additional 150 square feet for access); this is “new construction”
- A manufactured ADU delivered to your property
Therefore, there are charges for ADUs that meet the criteria above and two options are available:
Option 1: Obtain a new meter and separate service line to the proposed ADU structure.
Option 2: If the existing meter and service line have the capacity to provide adequate service to the primary dwelling and the ADU, obtain “dual service” using the existing service line to the property but installing a new meter for the proposed ADU.
Consult our ADU flow chart to see what your project requires.
- See NMWD Regulation 1 for more details on FRC costs. https://nmwd.com/wp-content/uploads/2021/08/Reg-01.pdf
- See Regulation 4 for more details on “dual services”. https://nmwd.com/wp-content/uploads/2020/04/Reg-04-1.pdf
Requirements for Fire Sprinkler Systems
The local fire authority (Novato Fire Protection District or Marin County Fire Department) determines if your ADU will require fire sprinklers. If they are required, replacement or upsizing of existing services may be necessary in order to provide the flow required for fire sprinkler systems.
The project must conform to NMWD Regulation 15 Mandatory Water Conservation Measures (or Regulation 17 for West Marin customers). Refer to the regulations for more details.