San Dimas · Building on your lot

Building on your lot in San Dimas

San Dimas sets its own rules for fences, accessory structures on corner lots and home businesses. Fence height depends on the yard, and one specific plan area has its own fence rules.

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Key points

Fence height: Fences are limited to 42 inches in the required front yard setback and 6 feet along side and rear property lines (city rule).
Corner lots: On corner lots, the city sets 10 feet for detached accessory structures and 20 feet for detached garages whose doors face the street.
Home businesses: Home businesses in residential zones need a home occupation permit; massage practices and massage technicians are not allowed.

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

Fences and walls

San Dimas code Fences are limited to 42 inches in the required front yard setback and 6 feet along side and rear property lines (city rule).

All 5 San Dimas rules on fences and walls, with the code text →

Sheds, garages and other accessory structures

San Dimas code What San Dimas's code adds
Side and rear setback	At least 10 feet from the street side property line. Applies: Detached accessory structures on corner lots in any residential zone. § 18.20.070 · code text No detached accessory structure in any residential zone shall be located at a distance less than ten feet from the street side yard property line. At least 20 feet from the side street property line. Applies: Detached garages on corner lots in residential zones, when the garage door faces the street. § 18.20.070 · code text No detached garage in any residential zone shall be located at a distance less than twenty feet from the side street property line when the garage door faces the street.

Running a business from home

San Dimas code What San Dimas's code adds
Permit	A home occupation permit is required. Applies: Home-based businesses in all residential zones and specific plans that allow homes as a primary use. § 18.184.010 · code text The general purpose of this chapter is to set forth provisions by which home based businesses, that are an accessory use to the primary residence, may be allowed in all residential zones and specific plans that allow residential as a primary use, provided that they comply with the prescribed standards to minimize impacts to residential neighborhoods.
Businesses not allowed	Massage practices and massage technicians § 18.184.030 · code text A. Massage practices and massage technicians.

Solar panels and EV chargers

San Dimas code A nondiscretionary permit is issued once the application meets the city checklist; the charger cannot be energized until approved. Administrative review; 1 inspection, scheduled within 2 business days of a request.

All 3 San Dimas rules on solar panels and EV chargers, with the code text →

Tree removal

San Dimas code Replacing each removed tree with up to 4 trees. Yes, a tree removal permit (the director's written approval) for mature significant trees.

All 5 San Dimas rules on tree removal, with the code text →

Swimming pools

San Dimas code What San Dimas's code adds
Maintenance and empty pools	An unattended, undrained pool on vacant premises is a public nuisance; whoever possesses the land must drain it immediately. Applies: When the premises are vacated or unoccupied. § 8.24.100 · code text Whenever there is located upon a lot or parcel an unattended, undrained swimming pool and such premises are vacated or unoccupied, such unattended, undrained, swimming pool is a public nuisance and shall be immediately drained by the person in possession of such land, either as owner, purchaser, lessee, tenant, licensee or otherwise.
Setback from property lines	At least 5 feet. Applies: Pools, spas, rockscapes and pool equipment, from side, rear and street-side property lines. § 18.20.220 · code text A minimum five-foot setback from side, rear, and street side property lines shall be required for swimming pools, spas, rockscapes, and pool equipment.

Building in a flood zone

San Dimas code What San Dimas's code adds
Floodplain permit	You need a development permit before construction or development starts. Applies: Within any special flood hazard area. § 15.60.110 · code text A development permit shall be obtained before construction or development begins within any area of special flood hazards established in Section 15.60.060. Application for a development permit shall be made on forms furnished by the floodplain administrator and may include, but not be limited to: plans in duplicate drawn to scale showing the nature, location, dimension, and elevation of the area in question; existing or proposed structures, fill, storage of materials, drainage facilities; and the location of the foregoing.
Height of the lowest floor	The lowest floor must be at or above the base flood elevation. Applies: New or substantially improved homes in special flood hazard areas; the lowest floor includes the basement. § 15.60.140 · code text New construction and substantial improvements of any structure shall have the lowest flood, including basement, elevated to or above the base flood elevation.

Building on a hillside

San Dimas code What San Dimas's code adds
Grading and retaining walls	Cuts should be no more than 12 feet high from bottom to top, including cuts held by walls. Applies: Housing sites; may be exceeded on difficult lots with a grading and planting plan approved by the planning commission. § 18.32.080 · code text Maximum vertical height of cuts, exposed or retained by walls, from toe to top, should not exceed twelve feet. Fills should be no more than 12 feet high from bottom to top, including fills held by walls. Applies: Housing sites; may be exceeded on difficult lots with a grading and planting plan approved by the planning commission. § 18.32.080 · code text Maximum vertical height of fills, exposed or retained by walls, from toe to top, should not exceed twelve feet.

Noise and construction hours

San Dimas code 7 a.m. to 8 p.m.; permit can allow other times; emergency work is exempt. Construction allowed 7 a.m. to 8 p.m. on Saturdays; not at any time on Sundays or public holidays.

All 6 San Dimas rules on noise and construction hours, with the code text →

Family child care homes

CA state law California law
Zoning	A small or large family child care home is a residential use and a use by right under all local ordinances, including zoning Health & Safety Code § 1597.45(a)
Business license or fee	A city or county may not charge a business license, fee or tax to run a family child care home Health & Safety Code § 1597.45(b)
Local rules	Local limits on height, setbacks, lot size, health and safety must be the same as for every other home in the same zone Health & Safety Code § 1597.45(e)
Small home	Up to eight children, counting the provider's own children under 10 who live there Health & Safety Code § 1596.78(c)
Large home	7 to 14 children, counting the provider's own children under 10 who live there Health & Safety Code § 1596.78(b)

Parking spaces required for homes

San Dimas code What San Dimas's code adds
Parking in the front yard	No parking or storage in the front yard Applies: Recreational vehicles, boats, camping trailers and utility trailers in single-family residential zones; "parking" means more than 48 hours in a row § 18.156.100 · code text No parking or storage may occur in the front yard. Allowed for up to 2 consecutive days for loading, unloading, prepping or cleaning, with a temporary parking permit Applies: Recreational vehicle on a paved driveway in the front yard § 18.156.100 · code text Temporary parking of an RV on a paved driveway in the front yard shall be allowed for up to two consecutive days for the purpose of loading, unloading or otherwise prepping and cleaning the RV, subject to a temporary parking permit which is attached thereto in plain sight, in the location designated by the director of development services.

Home alarm permits and false alarms

San Dimas code What San Dimas's code adds
How long an alarm may sound	An audible alarm must stop or automatically reset within 30 minutes of activation § 5.98.014 · code text An audible alarm shall terminate its operation or the audible alarm shall automatically reset within thirty minutes of its being activated.

Signs on homes

San Dimas code 1 nameplate per unit, not lit, up to 1 square foot; no sign permit required Not lit, up to 4 feet high and 6 square feet of sign face; no sign permit required

All 4 San Dimas rules on signs on homes, with the code text →

Other San Dimas rules on this

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

Keeping horses (§ 18.28.050) — single-family agriculture zone only
Limits on pets in residential zones (§ 18.20.060)
RVs, boats and trailers at a home (§ 18.20.030)
Grading in the hillside home zone (§ 18.32.080) — single-family hillside zone only
Park development fee (Ch. 3.26)

Who this affects

HomeownersContractorsDesigners

Frequently asked questions

How big can a shed or accessory building be in San Dimas?

On corner lots, the city sets 10 feet for detached accessory structures and 20 feet for detached garages whose doors face the street.

Can I run a business from my home in San Dimas?

Home businesses in residential zones need a home occupation permit; massage practices and massage technicians are not allowed.

What are the pool fence and setback rules in San Dimas?

San Dimas's code: At least 5 feet. (Pools, spas, rockscapes and pool equipment, from side, rear and street-side property lines.) (§ 18.20.220).

What are the rules for building in a San Dimas flood zone?

San Dimas's code: You need a development permit before construction or development starts. (Within any special flood hazard area.) (§ 15.60.110); The lowest floor must be at or above the base flood elevation. (New or substantially improved homes in special flood hazard areas; the lowest floor includes the basement.) (§ 15.60.140).

What extra rules apply to a hillside lot in San Dimas?

San Dimas's code: Cuts should be no more than 12 feet high from bottom to top, including cuts held by walls. (Housing sites; may be exceeded on difficult lots with a grading and planting plan approved by the planning commission.) (§ 18.32.080); Fills should be no more than 12 feet high from bottom to top, including fills held by walls. (Housing sites; may be exceeded on difficult lots with a grading and planting plan approved by the planning commission.) (§ 18.32.080).

Can I run a family child care home in San Dimas?

California law sets this for every city, including San Dimas: Zoning: A small or large family child care home is a residential use and a use by right under all local ordinances, including zoning (Health & Safety Code § 1597.45(a)); Business license or fee: A city or county may not charge a business license, fee or tax to run a family child care home (Health & Safety Code § 1597.45(b)); Local rules: Local limits on height, setbacks, lot size, health and safety must be the same as for every other home in the same zone (Health & Safety Code § 1597.45(e)); Small home: Up to eight children, counting the provider's own children under 10 who live there (Health & Safety Code § 1596.78(c)); Large home: 7 to 14 children, counting the provider's own children under 10 who live there (Health & Safety Code § 1596.78(b)).

How many parking spaces does a home need in San Dimas?

San Dimas's code: No parking or storage in the front yard (Recreational vehicles, boats, camping trailers and utility trailers in single-family residential zones; "parking" means more than 48 hours in a row) (§ 18.156.100); Allowed for up to 2 consecutive days for loading, unloading, prepping or cleaning, with a temporary parking permit (Recreational vehicle on a paved driveway in the front yard) (§ 18.156.100).

Do I need a permit for a home alarm in San Dimas?

San Dimas's code: An audible alarm must stop or automatically reset within 30 minutes of activation (§ 5.98.014).

General information, not legal advice.

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