ADU builders and rules in Lemon Grove

Lemon Grove ADU rules

Lemon Grove's ADU rules are in Municipal Code § 17.24.060, last updated in 2022, and summarized in the city's ADU development standards handout. ADUs and junior ADUs are allowed in the RL, RLM, RM, RMH, RP and CG zones and nowhere else. The handout says it is informational only; the code controls.

A few local details matter when you design. ADUs over 800 sq ft must keep the zone's open space and 15% of the lot in landscaping. The city asks for a map showing the distance to the nearest bus stop or transit center, because that distance decides both parking and the allowed height. And the design rule means an ADU should match the house, so check a catalog or prefab ADU against it early. If you're weighing layouts, see attached vs. detached ADUs and our junior ADU guide.

The state fire marshal's March 2025 map for Lemon Grove shows only Moderate and High zones in the city's area, with no Very High category in its legend. The city had to adopt the map by ordinance, and can add areas but cannot remove or downgrade them. Ask whether your lot is in a mapped zone, since that can change building code requirements.

Is Lemon Grove's ADU ordinance up to date?

No. On December 10, 2025, the state housing department sent the city a findings letter saying § 17.24.060 fails to comply with state ADU law, and gave it until January 9, 2026 to respond. HCD listed 15 problems. The ones that most affect homeowners:

• Unit count. The code allows one ADU and one junior ADU on a single-family lot. HCD says state law allows a converted ADU, a new detached ADU and a junior ADU together, for three units plus the house. On lots with more than one house, the code allows only one ADU; HCD says that limit must go.
• Multifamily lots. The code caps detached ADUs at two. HCD says state law allows up to eight with an existing multifamily building, as long as the ADUs don't outnumber the existing units.
• Height and setbacks. HCD said the code's flat 16 ft height cap must allow the higher state limits, that front setbacks can't block an 800 sq ft ADU, and that conversions can't be held to the house's setbacks.
• Junior ADU parking. The code requires replacing a garage converted to a junior ADU. HCD says the city can't require that parking.
• Design wording. HCD said terms like a “complimentary” style and materials of equal or better quality are subjective and must be removed.

The city's current handout already reflects some state rules, such as the 18 ft transit height and front-setback relief. Others it still lists, such as one ADU plus one junior ADU per single-family lot.

Lemon Grove pre-approved ADU plans

Lemon Grove has one pre-approved design so far: a 797 sq ft detached ADU by YWR Architects, with two bedrooms, one bathroom, a 112 sq ft porch, and stucco or wood-siding exterior options. It is drawn to the 2025 California codes. Architects and designers can submit their own plans; the city's ADU page says they must include architectural plans and structural drawings and calculations that aren't tied to one site.

• No changes allowed. The city says you can't reconfigure rooms, move windows or attach the unit to another structure and still get pre-approved processing.
• Not fully approved. The Building Department reviewed the plans for code compliance, but Engineering, Fire and Planning still review your site and are likely to have comments.
• You still need a site plan. Submit the pre-approved plan with a site-specific plan, and name the plan preparer in your project description.

The city doesn't say whether the plan is free to use, so ask the architect. For other options in the region, see our guide to pre-approved ADU plans in San Diego.

Lemon Grove ADU fees

Lemon Grove doesn't publish an ADU fee estimate. These are the line items we could confirm in the city's FY2025-26 master fee schedule and the school districts' pages. The schedule doesn't say which of them the city charges on an ADU, so ask for an estimate before you apply.

State law limits several of these. A city can't charge impact fees on an ADU under 750 sq ft, and above that the fee must be proportional to the main house. For utilities, state law bars new connection or capacity charges on most ADUs converted from existing space, and requires any charge on a new ADU to be proportionate to its burden on the system. Lemon Grove School District's fee page lists $3.21 per sq ft, effective July 13, 2024, and says the two districts split the state's maximum fee, 62% to Lemon Grove and 38% to Grossmont. A 750 sq ft ADU would pay about $3,308 in school fees at the current posted rates.

Fees are a small slice of the total. For build costs, see what an ADU costs in San Diego, try the ADU cost calculator, or read about ADU financing.

Getting a Lemon Grove ADU permit

Lemon Grove still takes building permits only in person, on paper. The Building Division doesn't accept online applications or digital plans. Here's the process the city describes:

1. Call Planning at (619) 825-3805 to confirm the project is allowed.
2. Print four sets of full-size plans (24” x 36”), folded to 9” x 24”, plus the building permit application.
3. Book a submittal appointment at (619) 825-3847. The counter at City Hall, 3232 Main Street, is open 7:30 a.m. to noon, Monday to Thursday, and closed Fridays.
4. Building, Engineering, Fire and Planning review the plans. Each round takes at least 30 days, and comments come back only after every department is done.
5. After approval, pay the issuance fee, which covers inspections. Inspections are booked on a voicemail line at (619) 825-3808.

Lemon Grove doesn't issue a separate certificate of occupancy; the signed inspection card serves as one. Once your application is complete, state law gives the city 60 days to approve or deny it. The city's handout lists what to put on the title page and site plan to cut down on resubmittals, including a table of every structure's square footage and the landscape percentage.

Demand is steady. The city's housing element reports 8 ADUs permitted in 2019 and 11 in 2020, with 40 applications in 2020, and sets a goal of 15 ADU permits a year, 120 by 2029. Before you sign, read how to hire an ADU contractor, check a contractor's license, and compare verified ADU builders in San Diego County.

Legalizing an unpermitted ADU in Lemon Grove

For a unit built without permits before January 1, 2020, the city's ADU page explains that under AB 2533 it can't deny a permit unless fixing the unit is needed to correct conditions that would make the building substandard, can't penalize you for the unpermitted unit, and generally can't charge impact or connection fees. The city posts a substandard housing checklist of those conditions. You may hire a licensed contractor for a confidential inspection before you apply. The handout adds that older permitted accessory rental dwelling units (ARDUs) are treated as ADUs.

Common questions