Windsor · Building on your lot

Building on your lot in Windsor

Windsor limits detached accessory structure height and total size, with larger sizes allowed by Minor Use Permit. Home businesses need a Zoning Clearance and are limited in space, customers and workers.

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Key points

Accessory structures: Windsor limits detached accessory structures to 15 feet and the main home's height; all together, 840 square feet without a Minor Use Permit.
Home business: Windsor home businesses may use 25% of the main dwelling or 400 square feet, whichever is greater, and have at most 8 customers daily.

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

Sheds, garages and other accessory structures

Windsor code What Windsor's code adds
Maximum height	Accessory structures may be no more than 15 feet tall. Applies: Detached residential accessory structures. They also may not be taller than the main structure. § 17.40.200 · code text The height of an accessory structure shall not exceed fifteen (15) feet.
Size or lot coverage	All residential accessory structures on the parcel may total no more than 840 square feet. Applies: Over 840 square feet needs a Minor Use Permit. ADUs, guest houses, pool houses and tiny homes do not count. § 17.40.200 · code text The maximum square footage of residential accessory structures is limited to eight hundred forty (840) square feet, which may be a single structure of eight hundred forty (840) square feet or multiple structures totaling eight hundred forty (840) square feet.
Side and rear setback	At least 5 feet from side and rear lot lines. Applies: Detached residential accessory structures. Not allowed in the front setback. On corner parcels, the zone's street side setback applies. § 17.40.200 · code text Accessory structures shall not be located within a required front yard setback, and shall maintain side and rear yard setbacks of at least five (5) feet, except that accessory structures on corner parcels shall maintain the street side setback required by the applicable zoning district.
Distance from the house	At least 6 feet between accessory structures, and between an accessory structure and the main home. Applies: Detached accessory structures and the main home. § 17.40.200 · code text A minimum separation of six (6) feet shall be maintained between the accessory structures and an accessory structure and the primary residence.

Running a business from home

Windsor code What Windsor's code adds
Space used	No more than 25% of the main home's floor area or 400 square feet, whichever is greater. Applies: General operating standard. § 17.40.120 · code text The use shall be confined to not more than twenty-five (25) percent of the floor area of the main dwelling nor more than four hundred (400) square feet of floor area, whichever is greater. No more than 1,000 square feet and no more than 40% of the main home's floor area. Applies: With Minor Use Permit approval. Includes storage areas and accessory structures. § 17.40.120 · code text In no case shall the home occupation, including storage areas and accessory structures, exceed either one thousand (1,000) square feet or forty (40) percent of the floor area of the main dwelling.
Customer visits	No more than 8 customers each day. Applies: General operating standard. § 17.40.120 · code text The home occupation shall be limited to eight (8) customers and two (2) deliveries each day. Up to 2 customer visits at a time. Applies: Only with Minor Use Permit approval. § 17.40.120 · code text Uses generating up to two (2) customer visits at a time or more than two (2) deliveries each day. No more than 10 customer or delivery trips each day. Applies: With Minor Use Permit approval. § 17.40.120 · code text In no case shall customer or delivery traffic exceed more than ten (10) trips each day.
Employees	Only people who live on the property may be employed. § 17.40.120 · code text Only persons residing on the property may be employed within the home occupation. No more than 1 employee who lives off-site. Applies: Business located in the home, with Minor Use Permit approval. § 17.40.120 · code text A use employing no more than one (1) person living off-site and working at the home occupation located in the dwelling.
Permit	A Zoning Clearance is required. § 17.40.120 · code text A Zoning Clearance shall be obtained in compliance with Chapter 17.54 (Zoning Clearance) to establish a home occupation. A Home Occupation Permit is required. Applies: Residential accessory structures used to house a home business. § 17.40.120 · code text Residential accessory structures may be used to house a home occupation, provided the home occupation obtains a Home Occupation Permit and complies with the standards established by this section. A Home Occupation Permit is required. Applies: Cottage food operations allowed by Sonoma County Environmental Health. § 17.40.120 · code text Cottage food operations allowed by Sonoma County Environmental Health require a Home Occupation Permit and shall comply with the requirements of this section. A Minor Use Permit is required. Applies: Activities that may not meet the standard operating rules. § 17.40.120 · code text The following are activities that may not comply with the operating standards in Subsection B. above, but may be allowed with Minor Use Permit approval, in compliance with Chapter 17.58 (Conditional Use permit and Minor Use Permit).

Lot splits under SB 9

Windsor code Each new lot must be 40% of the original lot's area. At most 1,200 square feet.

All 19 Windsor rules on lot splits under sb 9, with the code text and the state law underneath →

Tree removal

Windsor code What Windsor's code adds
Exemptions	Emergency removal is allowed when a protected tree is an immediate threat to public safety or welfare. Applies: Confirmed by the Director, police or Fire District; owner files documentation and a removal application within 5 days after. § 17.22.030 · code text Cases of emergency where the Director, a member of a law enforcement agency, or the Fire District, determines that a protected tree poses an imminent threat to the public safety, or general welfare. Exempt: removing or moving trees to keep required sight lines for traffic. Applies: As required by the Town's Traffic Engineer or Public Works Director. § 17.22.030 · code text Removal or relocation of trees necessary to maintain adequate line-of-sight distances as required by the Town's Traffic Engineer or Public Works Director. Exempt: removing trees to protect existing overhead power lines. Applies: As determined by the Public Works Director. § 17.22.030 · code text Removal of trees for the protection of existing overhead electrical power lines, as determined by the Public Works Director.
Penalty	The owner may face penalties if the Town finds no reasonable basis for an emergency. Applies: A tree removed during a claimed emergency. § 17.22.030 · code text If the Town determines that there was no reasonable basis for believing there was an emergency, the property owner may face penalties for violating this chapter.
Permit to remove	Yes, a permit is required. Applies: Removing or relocating protected trees in all zones, unless an exception applies. § 17.22.030 · code text The provisions of this section shall apply in all zoning districts for the removal or relocation of protected trees as identified in Subsection 17.22.030.F (Protected Trees). Exceptions to the provisions established in this section are outlined in Subsection 17.22.030.C (Exceptions), below. No Town review or approval is needed. Applies: A partly failed tree on private property threatening people or property; documentation and a removal application are due within 5 days after. § 17.22.030 · code text When a tree has partially failed and persons or property are threatened, the tree may be removed without Town review or approval.

Pets, chickens and bees

Windsor code What Windsor's code adds
Bees	Allowed; hives at least 5 feet from interior side and rear lines and 10 feet from a street-side line. Applies: Accessory to homes where the zone allows; other residential lots need Director approval; not in the required front setback. § 17.40.060 · code text Hives shall be setback a minimum of five (5) feet from interior side and rear property lines, ten (10) feet from a street side property line, and shall not be located within the required maximum front yard setback.
Permit	A Zoning Clearance is required. Applies: Before placing a hive on a lot. § 17.40.060 · code text A Zoning Clearance is required prior to locating a hive on a parcel.

Who this affects

HomeownersContractorsDesigners

Frequently asked questions

How big can a shed or accessory building be in Windsor?

Windsor limits detached accessory structures to 15 feet and the main home's height; all together, 840 square feet without a Minor Use Permit.

Can I run a business from my home in Windsor?

Windsor home businesses may use 25% of the main dwelling or 400 square feet, whichever is greater, and have at most 8 customers daily.

Do I need a permit to remove a tree in Windsor?

Windsor's code: Emergency removal is allowed when a protected tree is an immediate threat to public safety or welfare. (Confirmed by the Director, police or Fire District; owner files documentation and a removal application within 5 days after.) (§ 17.22.030); Exempt: removing or moving trees to keep required sight lines for traffic. (As required by the Town's Traffic Engineer or Public Works Director.) (§ 17.22.030).

Can I keep chickens or bees at my home in Windsor?

Windsor's code: Allowed; hives at least 5 feet from interior side and rear lines and 10 feet from a street-side line. (Accessory to homes where the zone allows; other residential lots need Director approval; not in the required front setback.) (§ 17.40.060); A Zoning Clearance is required. (Before placing a hive on a lot.) (§ 17.40.060).

General information, not legal advice.

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