Union City · Building on your lot

Building on your lot in Union City

Union City sets its own limits on fences in residential districts and bans some home businesses. Fence height depends on the yard and on what the lot abuts.

Ask about building on your lot in Union City See coverage

Key points

Fence height: Union City residential fences: 3 feet in front yards; 6 feet, plus up to 1.5 feet of lattice, in rear and interior side yards.
Banned businesses: Union City does not allow home businesses such as clinics, hospitals, barber shops, beauty parlors, tea rooms, animal hospitals and kennels.

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

Fences and walls

Union City code What Union City's code adds
Front yard height	No more than 3 feet above the ground. Applies: Front yard in a residential district. § 18.32.040 · code text When located in the front yard, the maximum height shall be three feet above the surface of the ground.
Side and rear yard height	No more than 6 feet, plus up to 1.5 feet of lattice on top. Applies: Required rear and interior side yards in a residential district. § 18.32.040 · code text In the required rear and interior side yards the maximum height shall be six feet as measured above the surface of the ground, except that an additional one and one-half foot of lattice may be added above a six-foot high fence. Up to 8 feet in a residential district. Applies: Rear or interior side yard next to flood channel, railroad, park, care or health facility, school, child care, commercial or industrial use, or major arterial. § 18.32.040 · code text Fences a maximum of eight feet in height may be allowed in the required rear yard or interior side yards when the yard abuts a flood control channel, railroad, park, licensed residential care or health facility, school, child care center, commercial use, industrial use or major arterials Up to 8 feet. Applies: Multifamily lots: fences around interior private open space at the end units of building clusters. § 18.32.040 · code text On lots developed with multifamily residential uses, fences a maximum of eight feet in height may be permitted to enclose interior private open space areas at the end units of building clusters. No more than 3 feet in the exterior side yard. Applies: Corner and reverse corner lots. Taller allowed 10 feet from side street line, at least 35 feet from front line, not in front of structure. § 18.32.040 · code text On corner and reverse corner lots, the maximum height shall be three feet in the exterior side yard, except that fences meeting the other requirements listed in Section 18.32.040(A) may be permitted when located 10 feet from the side street lot line and at least 35 feet from the front lot line, but not closer to the front lot line than the front face of the structure.

Running a business from home

Union City code What Union City's code adds
Businesses not allowed	Clinics, hospitals, barber shops, beauty parlors, tea rooms, tourist homes, animal hospitals and kennels § 18.08.280 · code text Clinics, hospitals, barber shops, beauty parlors, tea rooms, tourist homes, animal hospitals and kennels, among others, are not home occupations.

Lot splits under SB 9

Union City code One of the 2 new parcels may not be smaller than 40% of the original lot area. No single unit may be larger than 2,000 square feet.

All 14 Union City rules on lot splits under sb 9, with the code text and the state law underneath →

RV and boat parking

Union City code What Union City's code adds
Size limit	Vehicles over 20 feet long or 10,000 pounds or more may not park on any street at any time. Applies: Except in areas the City Council designates by resolution. § 10.36.195 · code text Vehicles having a length in excess of twenty feet and/or having a manufacturer's gross vehicle weight rating of ten thousand pounds or more shall not stop, stand or park on any highway, street or alley at any time except in areas designated by the City Council by resolution.
Parking on the street	Allowed only while actively loading and unloading. Applies: Applies to vehicles over 20 feet long or 10,000 pounds or more. § 10.36.195 · code text It is not a violation of this chapter to park said vehicles when such vehicles are:

Solar panels and EV chargers

Union City code What Union City's code adds
EV charger permit	Permits issue when the application meets the City checklist; no use until inspection and approval by City and utility. Applies: Applies to EV charging station permit approval; utility approval only as necessary. § 15.88.040 · code text Application approval/permit issuance does not authorize an applicant to energize or utilize the electric vehicle charging station, unless and until an inspection is performed and approval is granted by the City and the utility carrier as necessary.
Solar permit process	Administrative approval and all required permits once the checklist is confirmed; only 1 inspection is required. Applies: Applies to small residential rooftop energy systems eligible for expedited review. § 15.78.070 · code text Upon confirmation by the Building Official of the application and supporting documentation being complete and meeting the requirements of the California Solar Permitting Guidebook checklist, the Building Official shall administratively approve the application and issue all required permits or authorizations.

Tree removal

Union City code What Union City's code adds
Permit to remove	Yes; removal needs site development review, a use permit or Director approval. Applies: Applies to live trees 6 inches or more across at the base in the Open Space (OS) zone. § 18.92.150 · code text Removal of live trees of six inches or more in diameter at the base, shall be prohibited, except with the granting of site development review, use permit or approval of Director as applicable.
Protected trees	Live trees 6 inches or more in diameter at the base. Applies: Applies to properties in the Open Space (OS) zoning district. § 18.92.150 · code text Removal of live trees of six inches or more in diameter at the base, shall be prohibited, except with the granting of site development review, use permit or approval of Director as applicable.

Other Union City rules on this

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

Permit to keep more dogs (§ 8.22.020)

Who this affects

HomeownersContractorsDesigners

Frequently asked questions

How tall can a fence be in Union City?

Union City residential fences: 3 feet in front yards; 6 feet, plus up to 1.5 feet of lattice, in rear and interior side yards.

Can I run a business from my home in Union City?

Union City does not allow home businesses such as clinics, hospitals, barber shops, beauty parlors, tea rooms, animal hospitals and kennels.

Can I park an RV or boat at my home in Union City?

Union City's code: Vehicles over 20 feet long or 10,000 pounds or more may not park on any street at any time. (Except in areas the City Council designates by resolution.) (§ 10.36.195); Allowed only while actively loading and unloading. (Applies to vehicles over 20 feet long or 10,000 pounds or more.) (§ 10.36.195).

Do I need a permit for solar panels or an EV charger in Union City?

Union City's code: Permits issue when the application meets the City checklist; no use until inspection and approval by City and utility. (Applies to EV charging station permit approval; utility approval only as necessary.) (§ 15.88.040); Administrative approval and all required permits once the checklist is confirmed; only 1 inspection is required. (Applies to small residential rooftop energy systems eligible for expedited review.) (§ 15.78.070).

Do I need a permit to remove a tree in Union City?

Union City's code: Yes; removal needs site development review, a use permit or Director approval. (Applies to live trees 6 inches or more across at the base in the Open Space (OS) zone.) (§ 18.92.150); Live trees 6 inches or more in diameter at the base. (Applies to properties in the Open Space (OS) zoning district.) (§ 18.92.150).

General information, not legal advice.

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