What you can build
Lemon Grove ADU Regulations & Zoning
ADU regulations are complex, but when you’ve done this for 100+ projects, you know the details inside and out. We publish our insights because we want people to get accurate information… not just regurgitated bullet points. Our summary was last updated in February 2025.
KEY RULES AT A GLANCE
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
Number of ADUs Allowed
How many ADUs can you build in Lemon Grove?
On Lemon Grove single-family residential lots, you may build one ADU (either attached or detached) and one Junior ADU (JADUs have an owner occupancy requirement and must be converted from existing space within the primary residence).
2025 UPDATE: The 2025 HCD handbook clarified that you may have one single-family converted ADU, one JADU (a conversion of existing space up to 500 sf) and one detached ADU. Prior to this clarification, there was confusion if having a converted ADU plus a JADU would prevent a homeowner from building a detached ADU. Only one detached ADU is still allowed.
How many ADUs does Lemon Grove allow for multifamily properties?
Lemon Grove allows up to 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)
Effective Jan 2025 (SB1211): 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.
Non‐livable space within existing multi‐family structures may be converted into an ADU. Examples of areas that can be converted include storage rooms and garage spaces. The maximum number of ADU allowed in a multi‐family structure is equal to 25% of the number of existing multi‐family units in the structure. A minimum of one conversion ADU is allowed.
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, with front yard setback per zoning standards.
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?
Up to two detached accessory dwelling units shall be permitted on a lot with an existing multifamily dwelling, not to exceed 16′ in height.
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
Lemon Grove Municipal Code – Section 17.24.060 – Accessory buildings and uses
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