What We’ve Learned Building ADUs in Lemon Grove
Lemon Grove ADU Regulations & Zoning
Key Facts SnapShot
Size and Separation
Maximum size 1,200 square feet
Side/rear setbacks 4 feet
Two story Yes
Building separation 10 feet
Additional Requirements
Soils Report No
Building Verification Survey No
Coastal permit (in some areas) No
Stormwater Mitigation No
Permitting timeline
Standard Timeline: 3-5 months
Coastal Timeline: N/A
Permit Costs: $8-10/sqft
Number of ADUs Allowed
How many ADUs can you build in Lemon Grove?
On single-family lots in Lemon Grove, state law now supports a broader mix of ADU types than many homeowners previously realized. Under California law, a single-family property may combine:
- one standard ADU under the regular local-rules pathway
- one detached ADU up to 800 square feet
- one ADU created from existing space in the primary home or an accessory structure
- one JADU created from existing space in the primary residence, up to 500 square feet
HCD’s updated 2026 ADU Handbook explains that local agencies must allow the single-family combinations described in Government Code section 66323 and, in addition, must allow at least one unit described in section 66314.
However, note that local adoption will take some time.
Read more in our guide to how many ADUs you can build on a single-family property.
How many ADUs does Lemon Grove allow for multifamily properties?
Lemon Grove allows at least 2 detached ADUs for multifamily lots with an existing multi-family building. (Meaning: In order to build 2 ADUs, the property must already have at least a duplex on it, not just a single family dwelling)
Multifamily property owners are permitted to build as many ADUs as there are existing units, with a maximum of eight detached ADUs.
Additionally, a minimum of one accessory dwelling unit, or up to 25 percent of the existing multifamily units, is permitted within an existing multifamily dwelling, as a result of the conversion of non-habitable space including, but not limited to, storage rooms, boiler rooms, passageways, attics, basements, or garages.
Read more about the rules around how many ADUs you can build on a multifamily lot.
ADU Size & Building Constraints
What size ADU can you build in Lemon Grove?
Lemon Grove allows for a detached or attached ADU up to 1,200 sqft. Note that the ADU of >1000 sqft may not be larger than the primary home.
ADUs up to 800 square feet are exempt from lot coverage requirements. (Meaning: You can build an ADU of this size even if you’re maxed out on lot coverages).
What is the height requirement for an ADU in Lemon Grove? Can you build a 2-story ADU in Lemon Grove?
The maximum height for detached accessory dwelling units shall be sixteen feet. However, in some situations state law allows up to 20′, so a two story may be possible.
Due to recent state law change, detached ADUs within half a mile of major transit stops or high-quality transit corridors can use 4′ side & rear setbacks, up to 18 feet tall. An additional 2 feet can be added if the ADU’s roof pitch matches the primary dwelling. This 18’+2′ limit would allow for a two story unit.
The maximum height for internal and attached accessory dwelling units and junior accessory dwelling units shall be the same as the primary dwelling in the underlying zone.
Read more about two story ADUs & height limits and building an ADU above a garage.
What are the requirements of the exterior of the ADU?
An ADU shall utilize the same or complementary architectural style, exterior materials, and colors as the existing or proposed primary dwelling, and the quality of the materials shall be the same or exceed that of the primary dwelling.
Setbacks
What is the setback requirement for an ADU in Lemon Grove?
ADUs must have 4′ minimum setbacks from rear and side-yard property lines.
California state ADU law requires that front yard setbacks cannot prevent the construction of an ADU of at least 800 square feet, so an ADU under 800 square feet may encroach into front yard setbacks. If an ADU is above 800 square feet it must abide by front setbacks dictated by underlying zoning. Read more about setbacks and front yard ADUs.
What is the minimum distance the ADU must be from existing structures?
The minimum required distance between structures is 10′ from existing structures.
Additional Requirements
Does Lemon Grove require in-person submission of plans for an ADU?
Yes, Lemon Grove requires in-person submission of applications for an ADU, which adds some time and expense.
Does Lemon Grove require a soils report for an ADU?
No, Lemon Grove does not mandate soils reports for ADUs.
Does Lemon Grove require coastal development permits?
No areas are subject to Coastal requirements.
Multifamily
How many ADUs does Lemon Grove allow for multifamily properties?
Multifamily property owners are permitted to build as many ADUs as there are existing units, with a maximum of eight detached ADUs. This change is due to California state law and will pre-empt existing local laws that are not brought into conformance.
Additionally, a minimum of one accessory dwelling unit, or up to 25 percent of the existing multifamily units, is permitted within an existing multifamily dwelling, as a result of the conversion of non-habitable space including, but not limited to, storage rooms, boiler rooms, passageways, attics, basements, or garages.
Can you stack detached ADUs on top of each other?
This has yet to be tested with the city. However, code notes for lots with multifamily dwelling units, a detached ADU is subject to a maximum of 16 feet in height, so it is unlikely stacked ADUs are permissible.
Can you attach two ADUs to each other in Lemon Grove?
It is currently undetermined if two detached ADUs can be attached to each other; this will be subject to city interpretation.
Can you convert existing space to an ADU?
Yes, existing non-livable space may be converted to ADUs (e.g. storage areas and garages). The minimum number of ADU conversions allowed is one, up to a maximum equal to 25% of the number of existing multifamily units. This is in addition to the allowed number of detached ADUs..
Parking
What is the parking requirement for an ADU in Lemon Grove?
A parking space is not required for an ADU in any of the following instances:
- Within a one-half mile walking distance from public transit, which includes bus stops.
- Within an established historic district.
- Converted from the existing space of a primary residence or accessory structure, or are attached to an existing or proposed primary residence.
Effective Jan 2025 (SB1211): When a garage, carport, covered parking structure, or uncovered parking space is demolished or converted for construction of an ADU, replacement parking will not be required.
Where can a parking space be located?
If a parking space is required, it may be located within the setbacks and in an existing driveway as tandem parking. Parking spaces don’t need to be replaced when a garage, carport, or covered parking structure is demolished in conjunction with the construction of an ADU or converted to an ADU.
Additional Lemon Grove ADU Regulation Resources
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