In Coronado you can build a detached ADU up to 800 sq ft
guaranteed (1200 sq ft ceiling), 16 ft tall,
set back 4 ft from side and rear property lines.
Owner-occupancy is not required.
Parking is capped at 1 space and is waived entirely in six situations,
including within half a mile of transit. Because the state found Coronado's ordinance non-compliant, these are state figures and the city's own ordinance does not currently govern.
Gov. Code §§ 66310–66342 · 38 of 51 fields checked against statute text
California's Department of Housing and Community Development reviewed Coronado's accessory dwelling unit ordinance and found it does not comply with State ADU Law. Under Gov. Code § 66316 a non-compliant ordinance is null and void in its entirety, and state standards apply instead. Every figure below therefore comes from state statute, not from the city's code.
Ordinance status · derived from HCD review letters
Status was derived MECHANICALLY from the ingested HCD letter by literal keyword match ("failstocomplywithstateadulaw"), not by human review. Statutes cited: 65852, 66310, 66311, 66313, 66314, 66315, 66317, 66321, 66322, 66323, 66324, 66326, 66328, 66329, 66333, 66335, 66339, 66341, 66342. HCD letters expressly permit a jurisdiction to disagree with findings, so this is strong evidence but not an adjudication. Confirm with the jurisdiction before relying on it.
Quoted from the state's letter
What Coronado was told to change
All 23 of them, word for word. Nothing here is paraphrased, because paraphrasing a legal requirement is how error gets in.
provide · 2025-12-10
The City must provide a written response to these findings no later than January 9, 2026.
amend · 2025-12-10
The City must amend the Ordinance to refer to the correct Government Code sections.
amend · 2025-12-10
The City must amend the Ordinance to reflect all allowed ADUs with an existing or proposed single-family or multifamily dwelling.
multifamily lot counts
amend · 2025-12-10
The City must amend the Ordinance to allow an ADU to be attached to an accessory structure.
other · 2025-12-10
The City must allow the ADU to be taller.
amend · 2025-12-10
The City must amend the Ordinance to remove the imposition of development standards contained in the City's Zoning Ordinance on ADUs and JADUs.
JADU
amend · 2025-12-10
The City must amend the Ordinance to allow the maximum number of ADUs and a JADU pursuant to Government Code section 66323.
JADU
amend · 2025-12-10
The City must amend the Ordinance to note that maximum floor areas do not apply to the three types of 66323 units noted above.
size limits
amend · 2025-12-10
The City must amend the Ordinance to allow an ADU to be sold 14 Gov.
amend · 2025-12-10
The City must amend the Ordinance to reflect a property owner's discretion to rent an ADU or JADU with only the restriction of a 30-day minimum rental term.
JADU · rental term
amend · 2025-12-10
The City must amend the Ordinance to remove specific cooking appliances in an efficiency kitchen.
amend · 2025-12-10
The City must amend the Ordinance to remove the owner occupancy requirement when the JADU has its own bathroom or when the property is owned by a governmental agency, land trust or housing organization.
owner occupancy · JADU
amend · 2025-12-10
The City must amend the Ordinance to remove the six-month rental requirement and require that if a JADU is rented the rental be for a term longer than 30 days.
JADU · rental term
amend · 2025-12-10
The City must amend the Ordinance to remove the JADU owner occupancy requirement unless the JADU shares a bathroom with the main house.
owner occupancy · JADU
other · 2025-12-10
The City must not require that those off street parking 25 Gov.
parking
amend · 2025-12-10
The City must amend the Ordinance to remove the subjective standards on architectural style and material quality.
other · 2025-12-10
The City must correct and clarify this reference.
amend · 2025-12-10
The City must amend the Ordinance to indicate 750 square feet or less or 500 square feet of interior livable space or less for the exemption from impact fees.
size limits · impact fees
amend · 2025-12-10
The City must amend the Ordinance to allow the correct and maximum number of detached ADUs from an existing multifamily dwelling and to acknowledge all three detached ADU height allowances described in statute.
height · multifamily lot counts
amend · 2025-12-10
The City must amend the Ordinance to remove the requirement for these ADUs to comply with all standards in CMC section 86.
amend · 2025-12-10
The City must amend the Ordinance to note the exception in section 66328.
amend · 2025-12-10
The City must amend the Ordinance to remove the deed restriction requirement for ADUs.
amend · 2025-12-10
The City must amend the Ordinance to clarify that the review of the coastal development permit application and the construction permit application for an ADU happen concurrently.
Important, and worth checking before you rely on it: the state reviewed Coronado's ADU rules on 2025-12-10 and said they break state law. When that happens the law says the city's rules stop counting and the state's rules apply instead, which is usually better for you because the state's are more generous. A city is allowed to disagree with the state and keep its rules in place while it argues, so this is a strong position to take rather than a settled fact. The practical move: if a planner quotes you something stricter than the numbers below, ask which rule they are relying on given the state's findings, and confirm with the planning department whether the city has since fixed its ordinance.
What you can build. You can build a separate building in the yard, an addition attached to your house, or a conversion of space you already have, like a garage.
How many. On a normal single-family lot you can have 1 ADU, plus 1 "junior" ADU, which is a small unit carved out of the existing house.
How big. The city has to let you build at least 800 square feet. If you want two or more bedrooms, it has to allow up to 1000 square feet. For reference, 800 sq ft is roughly a one-bedroom apartment, about the size of a two-car garage.
How close to the property line. You need to leave 4 feet on the sides and 4 at the back. That is measured from your property line, not from the fence, and those are not always in the same place. If you are converting a garage that already sits closer than that, you can generally keep it where it is.
How tall. Up to 16 feet, which is a single storey with a normal roof. If your lot is within a half mile walk of a major transit stop, you get 18 feet instead.
Parking. You may need to add 1 parking space, but there are a lot of exemptions. The big one: if you are within a half mile walk of public transit, no parking is required. And if you convert your garage, nobody can make you rebuild the parking you lost.
Common questions
Is Coronado's ADU ordinance currently valid?
California's Department of Housing and Community Development found it non-compliant on 2025-12-10. Under Gov. Code § 66316 a non-compliant ADU ordinance is null and void in its entirety and state standards apply instead. The city may disagree and contest the findings, so confirm current status with the planning department.
How far from the property line does an ADU have to be?
4 feet from the side and rear property lines (Gov. Code s 66323(a)(2)). No setback at all is required if you convert an existing structure such as a garage that already sits closer (Gov. Code § 66314(a)(7)).
How tall can it be?
16 feet for a detached ADU (Gov. Code s 66321(b)(4)(A)), rising to 18 feet within half a mile walking distance of a major transit stop, plus 2 more feet to match the roof pitch of the main house. Attached ADUs may reach 25 feet or the primary dwelling's limit, whichever is lower.
Do I have to live on the property?
No. California bars a local agency from imposing an owner-occupant requirement on an ADU (Gov. Code s 66315). A junior ADU is different: owner-occupancy can still be required there.
Do I need to add parking?
At most one space (Gov. Code s 66314(d)(10)(A)), and six statutory exemptions remove it entirely, including within half a mile walking distance of public transit, within a historic district, or with a car share vehicle within one block (Gov. Code § 66322(a)). Converting a garage never obliges you to replace the lost parking.
Can I put it on Airbnb?
No. Rentals shorter than 30 days are barred, and for units approved on the by-right track that bar is mandatory rather than optional (Gov. Code § 66323(e)).
In the surrounding area
What the state found next door
How Coronado's neighbours fared in the same review process.
Across San Diego County the state has reviewed 7 ordinances and found 7 of them non-compliant.
Next steps
Before you rely on any of this
Bring up the state's findings letter for Coronado if a planner quotes you a stricter rule. The letter is public and is linked in the compliance output.
Find your exact lot size and where your property lines actually are. A survey beats a fence.
Call the planning counter and ask what zoning district your parcel is in, and whether any overlay applies (historic, hillside, fire hazard, flood).
Ask whether your lot is within a half mile walk of transit. That one answer changes parking and height.
If you are in an HOA, read the CC&Rs. State law limits outright HOA bans, but the details still matter.
Get the utility and sewer connection requirements in writing early. They are often the surprise cost.
Who builds them
No builder list for Coronado yet
Rather than list contractors we cannot evidence, this stays empty until Coronado
publishes permit records naming them or licence matching reaches the city. The
cities already covered show how the ordering works, and whichever contractor
you use, the rules above are the ones that govern the job.