Marin County · Building on your lot

Building on your lot in Marin County

Marin County's code applies only in unincorporated areas of the county. It sets coastal-zone limits for accessory structures and rules on home-business visits and licenses.

Ask about building on your lot in Marin County See coverage

Key points

Accessory height: County rule: in the coastal zone, detached residential accessory structures are limited to 15 ft in height.
Home businesses: County rule: home businesses need a business license and may have no more than 1 client appointment at a time.

Each rule below is marked Marin County code or CA state law and links to the section it comes from (checked October 2026). General information, not legal advice.

Marin County's code applies in the unincorporated areas of the county. Cities in Marin County have their own codes and their own pages.

Sheds, garages and other accessory structures

Marin County code What Marin County's code adds
Maximum height	A residential accessory structure can be at most 15 feet tall. Applies: For detached residential accessory structures in the coastal zone. § 20.32.130 · code text A residential accessory structure shall not exceed a height of 15 feet; Up to the height limit for a main building in that zoning district. Applies: For detached accessory structures in the coastal zone at least 40 feet from every property line that meet other rules, such as public views. § 20.32.130 · code text an accessory structure may be constructed to the maximum height allowed by the applicable zoning district for a primary structure, where the structure is located at least 40 feet from any property line and it meets any other applicable requirements At most 30 feet tall. Applies: For a detached parking structure with floor area built beneath it, in the coastal zone. § 20.32.130 · code text the maximum height of the detached structure shall be 30 feet.
Size or lot coverage	All detached accessory structures together: no more than 30% of the required rear-yard setback area. Applies: In the coastal zone. More needs Design Review approval. § 20.32.130 · code text The total aggregate floor area of all detached accessory structures shall not exceed 30 percent of the area contained within the boundaries of the setback required in the rear yard except with Design Review approval

Running a business from home

Marin County code What Marin County's code adds
Customer visits	No more than 1 client appointment at a time. § 20.32.100 · code text Any use which generates more than one client appointment at a time;
Employees	At most 1 non-resident employee. Applies: In the coastal zone, and only with a Use Permit. § 20.32.100 · code text A home occupation may be authorized to have a maximum of one non-resident employee with a Use Permit, in compliance with Chapter 22.48 (Conditional Use Permits). At most 1 non-resident employee. Applies: More than 1 needs a Conditional Use Permit. § 22.32.100 · code text A home occupation may have a maximum of one nonresident employee, and may only exceed this number with a Conditional Use Permit, in compliance with Chapter 22.48.
Permit	A county business license is required. § 20.32.100 · code text A business license shall be obtained/posted in compliance with Chapter 5.54 (Business Licenses) of the County Code for home occupations, which are allowed as accessory uses in all residential zoning districts.
Businesses not allowed	adult businesses; dance or night clubs; mini storage; storage of equipment, materials, and other accessories for the construction and service trades; vehicle repair (body or mechanical), upholstery, automobile detailing and painting; welding and machining § 20.32.100 · code text 1. Adult businesses; 2. Dance or night clubs; 3. Mini storage; 4. Storage of equipment, materials, and other accessories for the construction and service trades; 5. Vehicle repair (body or mechanical), upholstery, automobile detailing and painting; 6. Welding and machining;

Solar panels and EV chargers

Marin County code What Marin County's code adds
Solar height and setbacks	Roof-mounted systems may exceed the zone height limit by no more than 2 feet. Applies: Applies in coastal zoning districts; more than 2 feet needs findings of consistency with the Local Coastal Program. § 20.32.161 · code text May exceed the required height limit of the zoning district in which the project is proposed by no more than two feet. Free-standing systems no higher than 18 inches above grade at any point are exempt from yard setbacks. Applies: Applies in coastal zoning districts. § 20.32.161 · code text Exempt from the minimum yard setback requirements of the zoning district in which the project is proposed if the structure does not exceed a height of eighteen inches above grade at any point.

Tree removal

Marin County code What Marin County's code adds
Exemptions	Exempt if disease, damage or age makes long-term survival of the tree unlikely. Applies: Applies to any protected or heritage tree on a lot. § 22.62.040 · code text The general health of the tree is so poor due to disease, damage, or age that efforts to ensure its long-term health and survival are unlikely to be successful; Exempt if a pathogen or insects threaten nearby trees, as an arborist report or qualified professional finds. Applies: Applies to any protected or heritage tree on a lot. § 22.62.040 · code text The tree is infected by a pathogen or attacked by insects that threaten surrounding trees as determined by an arborist report or other qualified professional; Exempt if the tree may fall and is a safety hazard whose instability cannot be fixed. Applies: Applies to any protected or heritage tree on a lot. § 22.62.040 · code text The tree is a potential public health and safety hazard due to the risk of its falling and its structural instability cannot be remedied; Exempt if the tree is a public nuisance damaging improvements or interfering with public utilities. Applies: Applies to any protected or heritage tree on a lot. § 22.62.040 · code text The tree is a public nuisance by causing damage to improvements, such as building foundations, retaining walls, roadways/driveways, patios, sidewalks and decks, or interfering with the operation, repair, or maintenance of public utilities; Exempt if a Fire Inspector identifies the tree as a fire hazard. Applies: Applies to any protected or heritage tree on a lot. § 22.62.040 · code text The tree has been identified by a Fire Inspector as a fire hazard; Exempt if banning removal would conflict with CC&Rs that existed when the chapter was adopted. Applies: Applies to any protected or heritage tree on a lot. § 22.62.040 · code text Prohibiting the removal of the tree will conflict with CC&R's which existed at the time this Chapter was adopted; Exempt for up to 2 protected trees a year; no heritage trees, and none in Stream or Wetland Conservation Areas. Applies: Applies to developed lots. § 22.62.040 · code text The tree removal is on a developed lot and: 1) does not exceed two protected trees within a one-year timeframe; 2) does not entail the removal of any heritage trees; and 3) does not entail the removal of any protected or heritage trees within a Stream Conservation Area or a Wetland Conservation Area.
Permit to remove	Yes, a permit is required. Applies: Applies to Protected Trees, except removals that are exempt. § 22.27.030 · code text Protected Trees shall not be removed except in compliance with Section 22.62.040 (Exemptions), and as provided for in Chapter 22.62 (Tree Removal Permits).

Pets, chickens and bees

Marin County code What Marin County's code adds
Pet limit	No more than 3 dogs over 4 months old. Applies: Applies per lot, dwelling or other living space, unless other code sections or zoning allow more. § 8.04.185 · code text it is unlawful for any person to keep or harbor more than three dogs which are over the age of four months on any lot, premises, dwelling, building, structure, boat or living accommodation.

Other Marin County rules on this

Marin County's code also has these chapters. We have not summarized their values on this page yet; read them in the library.

SB 9 housing development standards (§ 22.32.184)
SB 9 urban lot splits (§ 22.80.064)
No parking of oversized vehicles (§ 15.36.091) — on public streets with posted signs
Living in campers, house cars and trailers (Ch. 7.52)

Who this affects

HomeownersContractorsDesigners

Frequently asked questions

How big can a shed or accessory building be in Marin County?

County rule: in the coastal zone, detached residential accessory structures are limited to 15 ft in height.

Can I run a business from my home in Marin County?

County rule: home businesses need a business license and may have no more than 1 client appointment at a time.

Do I need a permit for solar panels or an EV charger in Marin County?

Marin County's code: Roof-mounted systems may exceed the zone height limit by no more than 2 feet. (Applies in coastal zoning districts; more than 2 feet needs findings of consistency with the Local Coastal Program.) (§ 20.32.161); Free-standing systems no higher than 18 inches above grade at any point are exempt from yard setbacks. (Applies in coastal zoning districts.) (§ 20.32.161).

Do I need a permit to remove a tree in Marin County?

Marin County's code: Exempt if disease, damage or age makes long-term survival of the tree unlikely. (Applies to any protected or heritage tree on a lot.) (§ 22.62.040); Exempt if a pathogen or insects threaten nearby trees, as an arborist report or qualified professional finds. (Applies to any protected or heritage tree on a lot.) (§ 22.62.040).

Can I keep chickens or bees at my home in Marin County?

Marin County's code: No more than 3 dogs over 4 months old. (Applies per lot, dwelling or other living space, unless other code sections or zoning allow more.) (§ 8.04.185).

General information, not legal advice.

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