Garden Grove ADU Permit Guide (2026)

By ADU Home Construction · Last reviewed: November 4, 2026

The ordinance the counter is using

Garden Grove has a local ADU ordinance. It is Municipal Code Chapter 9.54. The chapter history includes Ordinance 2966, dated August 12, 2025. Section 9.54.020 allows an ADU on a lot zoned for single-family or multifamily use that has a proposed or existing legal dwelling. A junior ADU has to be inside a proposed or existing legal single-family dwelling on a lot zoned to allow single-family use.

Section 9.54.070(E) says the city shall not apply a local standard to the extent state law prohibits it, including Government Code section 66323. That sentence matters when an older handout and the code disagree. This page follows Chapter 9.54 as posted on eCode360 on November 4, 2026, and it flags the city's FAQ where the FAQ is older. The statewide background is our legal guide and the HCD ADU Handbook.

The city's ADU page is the public front door. Planning questions on the FAQ go to (714) 741-5312 and planning@ggcity.org. City Hall is at 11222 Acacia Parkway, Garden Grove, CA 92840, and the general phone on the city footer is (714) 741-5000. Posted City Hall hours are Monday through Thursday, 7:30 a.m. to 5:30 p.m., with alternating Fridays from 7:30 a.m. to 5:00 p.m. Which Friday is open changes. Use the city's Friday and holiday closure calendar instead of assuming a Friday you saw on the website is a permanent schedule.

Apply in GG Ready

Pre-approved ADU plans are submitted online through GG Ready. The login the city publishes is gardengrove.vivasoft.io. The development-access page lists ADU and junior ADU work with the other residential permits. If your project was submitted before February 13, 2023, that same page sends you to a different place to check status or schedule an inspection. Do not expect a 2022 file to show up in the new portal.

The ADU Go page says the first step is still the Planning Division. A project that uses a pre-approved plan has to comply with the ADU ordinance for setbacks, building height, building separation, and in some cases lot coverage and rear-yard open space.

Four free city plans, and what they leave out

ADU Go lists four city-owned plans and says they are offered free of charge. The same paragraph says they are architectural plans only. They do not include structural sheets or site-specific Title 24 sheets. You still prepare a site plan, Title 24, structural plans, and structural calculations for the plan-check submittal. Each of the four plans lists a porch and no patio.

• ADUGO-CP-1: 447 square feet, studio (0 bedrooms), 1 bathroom, porch yes, patio no.
• ADUGO-CP-2: 630 square feet, 1 bedroom, 1 bathroom, porch yes, patio no.
• ADUGO-CP-3: 750 square feet, 2 bedrooms, 2 bathrooms, porch yes, patio no.
• ADUGO-CP-4: 1,000 square feet, 3 bedrooms, 2 bathrooms, porch yes, patio no.

A second block on the same page is for plans that are not city-owned. The city says those plans are prepared by private architects, that "architect" on that page also includes engineers and designers, and that the fee is set by the architect of record. On November 4, 2026 that block said "Coming Soon." The city has not posted a designer name there yet.

"Free" means the city plan set. It does not mean the structural engineering, the Title 24 sheets, the permit fees, or the construction contract.

Flood Zone A closes the pre-approved set

ADU Go says, in bold, that a property may not use the pre-approved ADU plans if it is in a Special Flood Hazard Area, which the page calls Flood Zone "A." The city's flood explainer is Questions about the flood zone. A lot in that zone can still ask Planning about a custom ADU. It cannot use these four plan sets.

How many units Chapter 9.54 allows

Section 9.54.030, except as Government Code section 66323 provides otherwise, allows no more than one ADU, and no more than one junior ADU, on a single-family lot. On a lot with an existing multifamily building, the code allows no more than 8 detached ADUs, and not more than the number of existing multifamily units. A lot proposed for multifamily housing can have no more than 2 detached ADUs. Converted ADUs in non-livable space of an existing multifamily building are limited to 25 percent of the existing units, rounded down, and at least one.

The city's FAQ still says a multifamily lot can have up to two detached ADUs. That line does not match section 9.54.030 after Ordinance 2966. Use the code, and ask Planning if your lot is the existing-building case or the proposed-building case.

Today, a single-family lot is still one ADU and one junior ADU unless section 66323 requires a different ministerial unit. Starting January 1, 2027, AB 956 (Quirk-Silva), Chapter 791, Statutes of 2026 says a city does not have to ministerially approve a junior ADU on a lot where two detached, new-construction ADUs were built under the new Government Code section 66323(a)(2). A city may still cap each of those detached units at 800 square feet of livable space and apply the height limits in section 66321(b)(4). Local ordinances have to follow that on January 1, 2027. Section 9.54.070(E) already tells Garden Grove not to apply a local rule the state forbids. See the 2026 law update.

Size, height, setbacks, and separation in the code

Section 9.54.040 sets minimum sizes: 150 square feet for an efficiency unit, 220 for a studio, 500 for one bedroom, and 700 for two or more bedrooms.

Attached maximums: a studio or one-bedroom attached ADU is limited to 850 square feet or 50 percent of the primary dwelling, whichever is less. If the primary dwelling is under 1,600 square feet, that attached unit may be up to 800 square feet. An attached unit with two or more bedrooms is limited to 1,200 square feet or 50 percent of the primary, whichever is less, with the same 800 square foot floor when the primary is under 1,600 square feet.

Detached maximums in the same section: 850 square feet for a studio or one bedroom, and 1,200 square feet for two or more bedrooms. A conversion has no maximum if it does not add floor area. An accessory-building conversion may expand by up to 150 square feet for ingress and egress.

A porch or patio attached to the ADU can be up to 80 square feet. An attached one-car garage can be up to 250 square feet inside, with a minimum interior parking size of 10 by 20 feet, and that parking area cannot be used for storage or equipment. The ADU plus porch, patio, and garage together cannot exceed 1,530 square feet.

The FAQ still says that if the lot also has a junior ADU, a new ADU is limited to 800 square feet. That 800 square foot cap is not the maximum written in section 9.54.040. State law lets a city cap the one detached unit it must allow under section 66323 at 800 square feet, while the local ordinance allows larger detached units that meet the local standards. Read both, and confirm with Planning which cap applies to your combination of units. This page does not treat the FAQ's 800 square foot line as the ordinance maximum.

Setbacks in section 9.54.040: the front setback is the same as for other structures, except the unit may encroach only as far as needed to build an 800 square foot ADU. A broader sentence in the chapter says that if floor area ratio, front setbacks, building separation, lot coverage, open space, or minimum lot size would stop an attached or detached ADU of at least 800 square feet, that standard is waived to the extent needed to allow an ADU of up to 800 square feet. Side and rear setbacks are a minimum of 4 feet for a new attached or detached ADU, for allowed expansions, and for a new garage, porch, or patio. A conversion keeps the existing setback if it is enough for fire and safety. A new ADU garage that opens onto a street or alley needs a 20 foot setback. If the driveway meets the alley at a right angle, the garage cannot be closer than 20 feet to the alley centerline, and it needs at least 5 feet from the property line.

Separation: 6 feet between a detached ADU and the primary dwelling, and 6 feet between the ADU and other structures that are not attached to it. Those separation rules do not apply to a conversion that does not expand.

Height: a detached ADU is generally not more than 16 feet. It may be 18 feet on a lot with an existing or proposed multifamily multistory dwelling. It may be 18 feet within one-half mile walking distance of a major transit stop or a high-quality transit corridor, as Public Resources Code section 21155 uses those terms, plus up to 2 feet more if that is what it takes to align the roof pitch with the primary dwelling. An attached ADU is not over 25 feet or the primary dwelling's height limit, whichever is lower, and it is not over two stories. A conversion has no extra height limit. Height is measured from the ground to the highest point of the roof.

The FAQ still says a new ADU cannot be two stories and that the height limit is 16 feet. That answer does not include the 18-foot cases in section 9.54.040. Use the code.

The city's 2021 new-ADU handout is older than Ordinance 2966. Use Chapter 9.54 for size, height, setbacks, parking, and open space.

Design: except where Government Code section 66323 or the fire and building codes say otherwise, the roof and walls match the primary dwelling. A pre-approved plan under Government Code section 65852.27 is deemed to comply with the design match.

Parking on a Garden Grove lot

Section 9.54.040 requires one off-street space for a new attached or detached ADU. That space may be in a setback or tandem, unless the Director finds tandem or setback parking infeasible because of topography or fire and life safety. The space is in addition to the primary home's parking. A garage, carport, or covered or uncovered space that is demolished or converted for the ADU does not have to be replaced.

No ADU parking is required if the unit is within a one-half mile walk of public transit, in an architecturally and historically significant historic district, a conversion, on a street where on-street permits are required but are not offered to the ADU occupant, or within one block of a car-share vehicle. A junior ADU needs no additional off-street parking beyond what was required when the primary dwelling was built, under section 9.54.050. The longer garage discussion is our garage conversion guide, read next to section 66314. Garden Grove's replacement rule for an ADU is the sentence in section 9.54.040, not a guess from another city.

Junior ADUs, rentals, and owner occupancy

Section 9.54.050 puts a junior ADU inside the walls of a proposed or existing single-family dwelling, including an existing attached garage. The maximum is 500 square feet. It needs a separate entrance and an efficiency kitchen. The bathroom can be its own or shared. If it is shared, the junior unit needs an interior entrance to the main living area or direct access to the shared bathroom. A detached garage cannot be a junior ADU. The FAQ agrees with that limit.

The deed restriction is recorded with the County Recorder before the building permit, and a copy goes to the Director. It says there is no more than one junior ADU and one ADU, the unit cannot be sold separately, and it states the size and attributes. The code also says the owner must occupy the junior unit or the rest of the primary dwelling, unless the owner is a governmental agency, land trust, or housing organization, and that the unit cannot be modified without the Director's consent.

Section 9.54.060 says an ADU or junior ADU that is rented has to be rented for 30 days or longer. A stay under 30 days is prohibited. ADU owner occupancy is not required. The code's junior-ADU owner-occupancy rule, quoted above, is broader than the statute now in force. Government Code section 66333(b), as amended effective January 1, 2026, requires owner occupancy only when the junior ADU shares sanitation facilities. It is not required when the junior unit has its own sanitation, or when the owner is a governmental agency, land trust, or housing organization. The FAQ still says state law requires owner occupancy for any junior ADU. That FAQ line, and the broader sentence in section 9.54.050, both need to be read with section 9.54.070(E) and section 66333(b). Confirm the deed-restriction wording with Planning before you record it. The statewide write-up is the junior ADU guide.

Section 9.54.060 also says the unit cannot be sold separately except as Government Code section 66341 allows.

Sixty days, or thirty if the plan is already approved

Section 9.54.070 requires a building permit. Fire sprinklers are not required for the ADU if they are not required for the primary dwelling, and building the ADU does not by itself force sprinklers into the existing primary dwelling. The Director approves or disapproves a complete application ministerially, without a public hearing, within 60 days. A detached ADU that uses a city pre-approved plan from the current triennial California Building Standards Code cycle, or a plan identical to one the city approved in that cycle, is decided within 30 days. A delay the applicant causes can pause the clock. If the ADU is filed with a new house, the city may wait until it acts on the new house.

The state clock is the same 60 days in Government Code section 66317, with a 15-business-day completeness check and a deemed approval if the city is late. Our SB 543 timeline is the checklist for that statute. Garden Grove's 30-day line is local, and it applies only to the detached pre-approved case in section 9.54.070. The city also says it will not require you to correct a nonconforming zoning condition, a building violation, or an unpermitted structure that is not a health or safety threat and is not affected by the ADU.

Other local rules in the chapter: an attached or converted ADU needs exterior access, the city cannot require a passageway, laundry hookups are required, the water heater is separate and cannot sit in an exterior enclosure, mechanical equipment is screened and keeps a 3-foot path if it sits between a structure and the property line, and trash containers follow the Garden Grove Sanitary District, with a 38 by 38 inch spot per container.

Impact fees, and the one square foot at 750

Section 9.54.090 says no impact fee is required for an ADU that is less than 750 square feet. An ADU of 750 square feet or more is charged in proportion to the primary dwelling. The code says "impact fee" does not include a connection fee, a capacity charge, a planning fee, a plan check fee, or a building permit fee.

State law, in section 66311.5, says an ADU of 750 square feet of interior livable space or less is not charged an impact fee. Garden Grove's ordinance says "less than 750." At exactly 750 square feet, the two sentences are one square foot apart. Section 9.54.070(E) says the city does not apply a local rule the state prohibits. Ask Planning which sentence the cashier uses for a unit that is exactly 750 square feet.

Starting January 1, 2027, SB 1117 (Cervantes), Chapter 809, Statutes of 2026 keeps the no-fee rule for an ADU of 750 square feet of interior livable space or less, and for a junior ADU of 500 square feet or less. On a lot with up to two ADUs, an impact fee on a larger ADU is still charged in proportion to the main home, and only on the square feet above 750. A lot with more than two ADUs keeps today's proportional rule on the whole unit. The change applies to charter cities. It does not set a dollar amount, and connection charges stay separate. Local ordinances have to follow it on that date.

The ADU page links a Public Works impact-fee PDF. Ask Public Works for the dollar amount on your lot. The 2026 user fee schedule and the FY 2025-26 building and planning fee schedule do not label a separate ADU price. Ask the counter which lines apply to your permit.

Coastal Zone, HOAs, and the other city papers

Garden Grove does not appear on the Coastal Commission's June 2025 list of coastal jurisdictions. A coastal development permit is not the extra step it is in some Orange County beach cities. If a map ever shows otherwise for a specific parcel, follow the map.

The city does not publish a separate HOA step in Chapter 9.54. Statewide, Civil Code sections 4751 and 714.3 make void a covenant that effectively prohibits or unreasonably restricts an ADU or junior ADU on a lot zoned for single-family use. Reasonable objective design limits can remain. Starting January 1, 2027, AB 956 applies those sections to a lot zoned to allow single-family residential use. The current rule stays until that date.

The ADU page also links ADU 101 slides, an ADU water meter application, and the FAQ in four languages: English, Vietnamese, Spanish, and Korean. The Vietnamese file name includes a 2021 revision date. Treat the FAQ as a help sheet, and treat Chapter 9.54 as the ordinance.

Official Garden Grove links

Questions homeowners ask

Last reviewed and sources

Last reviewed: November 4, 2026.

• City of Garden Grove, ADU. FAQ languages, City Hall hours, Public Works fee link.
• ADU Go. Four free plans, architectural scope, Flood Zone A, GG Ready submittal, non-city plans marked Coming Soon.
• Chapter 9.54. Counts, size, height, setbacks, parking, junior ADUs, 60-day and 30-day review, impact fees, and the state-law savings clause in section 9.54.070(E).
• ADU FAQ (English). Several answers are older than Ordinance 2966. Those conflicts are called out above.
• GG Ready. Projects before February 13, 2023 use a different status page.
• 2026 user fees and the FY 2025-26 building and planning fee schedule. No ADU dollar line quoted.
• Gov. Code section 66333, section 66317, and section 66311.5.

Nearby city guides: Anaheim, Santa Ana, and Irvine. All of the city pages are on the California city guides hub. How to check a builder yourself is in how to find an ADU contractor.