Lemon Grove Accessory Dwelling Unit Regulations

Introduction to Accessory Dwelling Units

An accessory dwelling unit, commonly called a granny flat or in-law suite must exist on a lot that’s zoned single-family. It has its own entrance, separate from the primary house, as well as a kitchen, bathroom and living space. These units can be rented, year-round, and add a lot of value to a property.


ADU’s are allowed on lots with one existing single-family dwelling in the RL or RL/M, or RM/H zones.

ADU’s are not allowed on lots that have an existing guesthouse or guest living quarters. However, guesthouses or guest living quarters may be converted into an ADU.

Lot size in Lemon Grove

There is no minimum or maximum lot size requirement to build an accessory dwelling unit.

Min/Max Building Sizes

Your maximum build size differs depending on whether your accessory unit is attached or detached from the primary home.

Attached ADU: The floor area of the ADU should not be more than 50% of the existing residence up to 1,200 square feet. For example, if your existing house in 2,500 sq. ft., the attached ADU cannot exceed 1,200 sq. ft. in size.

Detached ADU: For a detached ADU, the total floor space area of the ADU should not be more than 1,200 square feet, regardless of the size of the primary residence.

Height Restrictions

There are no height restrictions listed in the ordinance.

Parking in Lemon Grove

ADUs are required to have one off-street parking spot, which may be provided as tandem parking or within setbacks (given there are no safety concerns).

Off-street parking is not required if:

  • The ADU is within ½ mile of a public transit stop
  • The ADU is within an architecturally or historically significant historic district
  • The ADU is attached to the primary residence or an existing accessory structure
  • The ADU is within an area where on-street parking permits are required but not available to occupants of the ADU
  • The ADU is within one block of a car-share vehicle’s pick-up location (established by the city)

If the ADU is created through garage conversion replacement parking must be supplied.


Attached and detached ADU’s should follow the same yard and setback requirement of the main residence.

Detached ADU’s should not be closer than 10 feet from any other buildings on the property.

ADU’s that created through garage conversions are allowed within the setbacks.

Owner Occupancy

ADU’s cannot be sold separately from the primary residence.

Rentals in Lemon Grove

California passed Senate Bill 1069 in an effort to increase the supply of housing to the state. For this reason, any accessory dwelling unit may be used for a long-term rental.

How to Evaluate ROI

Building an accessory dwelling unit, especially if you intend to keep the property for a few years, represents an enormously beneficial opportunity to maximize your property.

By constructing an accessory dwelling unit you are adding additional square footage to the property. So if you can build a unit for $275 a square foot, but the average value of homes in your neighborhood are worth $400 a square foot you are gaining instant equity through the project. Plus, you also now have the added benefit of a flexible space that can be rented or used for family.

Additional notes

Dwellings that are modified to include an ADU should retain the appearance of a detached single-family dwelling.

ADU’s should keep with the architectural style of the neighborhood, in terms of siding and roof materials, roof overhang, and window treatments.

New or separate utility connections to ADU’s are not required except if it’s within the RM or RM/H zones.

Fire sprinklers for ADU’s are not required unless they exist in the primary residence.

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