ADUs
Can my HOA stop my ADU?
No, not on a single-family lot. It can still review the design, and it can still slow you down if you file in the wrong order. Here is what the law says and how we sequence it.
Not if it is an ADU or junior ADU on a lot zoned for single-family use. Since 1 January 2020, Civil Code §4751 has made any CC&R or other HOA rule void to the extent it effectively prohibits or unreasonably restricts one, and the HOA keeps only reasonable restrictions that do not unreasonably raise the cost or effectively block the unit. The protection does not cover an SB 9 lot split or a second primary home, and an attorney should read your specific CC&Rs before you rely on any of this.
What the statute actually says
Civil Code §4751 was added by AB 670, signed on 30 August 2019. It sits in the Davis-Stirling Act, the part of the Civil Code that governs homeowners associations. Subdivision (a) reaches two kinds of private rule: any covenant or restriction in a deed or other instrument affecting a planned development, and any provision of the association's governing documents. If either one effectively prohibits or unreasonably restricts the construction or use of an ADU or a junior ADU on a lot zoned for single-family residential use, that provision is void and unenforceable (current text on leginfo).
Subdivision (b) is the part the HOA will quote back to you. The section does not apply to reasonable restrictions, which the statute defines as restrictions that do not unreasonably increase the cost of building a unit that complies with state ADU law, and do not effectively prohibit or extinguish the ability to build one. So the HOA keeps a say. It loses the veto.
A twin provision, Civil Code §714.3, applies the same rule to any deed restriction on real property, HOA or not. Since 30 June 2025 it also says reasonable restrictions shall not include any fees or other financial requirements. That sentence came from AB 130, and the state housing department applies it to CC&Rs in its handbook.
The protection turns on the words in the statute. The unit has to be an ADU or a junior ADU. The lot has to be zoned for single-family use. The unit has to meet state ADU law, now Government Code §66314 onward for ADUs and §66333 onward for junior ADUs. And the rule being challenged has to come from a planned development's covenants or governing documents, or under §714.3 from any recorded instrument. If you own a condo, or your home sits on land the association owns in common, the analysis is different and belongs with an attorney.
What "reasonable" has meant in practice
The best official guide to the line is the California Department of Housing and Community Development's ADU Handbook (March 2026 edition), which has a section on HOAs. It says HOAs may impose "some limited objective standards" such as specific materials, architectural styles, or other design and aesthetic rules, within reason. Those standards may not be more stringent than state ADU law in a way that unreasonably raises cost or effectively blocks the unit.
HCD then lists what crosses the line. These are its examples, paraphrased:
- A review that runs longer than the 60 days a city gets to act on an ADU permit, or that significantly delays construction or use.
- A required change to the application that would cost the owner substantial money or force them to drop the project.
- A condition that would force the owner to re-apply for, or amend, a building permit application that already substantially complies with state law.
- Requiring the neighbours to approve, or treating their objection as a reason to deny.
- Restricting where the unit goes so tightly that it becomes infeasible or unusable.
- Requiring structural elements or design changes beyond state ADU law that would extinguish the ability to build or use the unit.
- Any restriction that is not objective, or that the owner could not have known before applying.
Put side by side, the pattern is clear enough to plan around.
| What the HOA asks for | Where it likely falls | Why |
|---|---|---|
| Roofing and siding that match the main house | Usually reasonable | Materials and style are the examples HCD gives of permitted standards |
| An exterior colour from the community palette | Usually reasonable | An aesthetic standard that costs little to meet |
| A setback larger than the city's | Depends on the lot | Allowed unless it pushes the unit somewhere infeasible or unusable |
| Work hours and a staging plan during construction | Usually reasonable | Governs how you build, not whether you can |
| A size cap below what state law makes a city allow | Likely unreasonable | State law bars a city from capping an ADU below 850 sq ft (1,000 with more than one bedroom) and requires it to permit up to 800 sq ft; an HOA standard more stringent than state law is out |
| No renting the ADU | Likely void | Civil Code §4751 covers use, and §4740 and §4741 protect renting an ADU in a common interest development |
| Neighbour sign-off | Likely void | Named in HCD's list |
| A flat no | Void | The core of §4751(a) |
| A review fee or deposit | Unsettled | §714.3(b) bars fees as a reasonable restriction; the statute does not spell out how far that reaches |
The rental point deserves one more line. The legislature's stated intent in AB 670 was ADUs "used for rentals of terms longer than 30 days", and HCD notes a city may require rentals to run longer than 30 days. Whether an HOA may ban short-term rentals of an ADU is a separate question; ask an attorney.
The city and the HOA are two separate tracks
This is the part most homeowners get wrong in both directions. The city does not enforce your CC&Rs. The HOA does not issue building permits. Each runs its own process, and neither one's approval stands in for the other's.
HCD is blunt about the city side. Under Government Code §66315 and §66317(c), a city must approve an ADU through a ministerial process, and no other local policy may be applied to the decision. An HOA may not review or influence that approval, and a city that lets an HOA into any part of the ADU application process is itself violating state ADU law. The County of Santa Clara says the same thing in plain words on its SB 9 page: it does not enforce private CC&Rs.
The HOA side is governed by Civil Code §4765 whenever the governing documents require approval before an owner makes a physical change. The association must run a fair, expeditious procedure written into its governing documents, with prompt deadlines. A decision must be made in good faith and may not be arbitrary or unreasonable. It may not violate any law, including land use law. A denial has to be in writing with the reason, and it must describe how to get reconsideration by the board at an open meeting. The association also has to tell members once a year what its approval requirements are.
A city permit does not let you skip the HOA, and an HOA approval does not let you skip the city. If you build on a permit alone, the HOA can still enforce its reasonable restrictions, and the fight happens after the siding is on. If you wait for the HOA before drawing anything, you lose months for no reason. The answer is to run them in parallel from the same drawings.
The order we recommend
Read the CC&Rs and the architectural guidelines first
Before anyone draws. The guidelines usually hold the material and colour rules, and those belong in the first plan set. If anything in them looks like a ban or a size cap, that is the moment to get an attorney's read, not after plan check.
Have an informal conversation with the committee
Ask whether the committee will look at a site plan and an exterior description before a formal application, and how often it meets. An early read on the exterior saves a redraw.
Draw to both rulebooks at once
Your architect or designer draws to the city's standards and the HOA's objective guidelines together. We are the builder: we price and build the approved set, and we flag anything on the drawings that will be expensive to build.
File both applications with the same drawings
The building permit and the architectural review application go in together, from the same set. HCD treats an HOA condition that forces a re-application on a compliant permit as unreasonable, which is one more reason the HOA should see what the city sees.
Get the HOA decision in writing before work starts
Do not start work or order exterior materials on an HOA project until both approvals are in hand. If the answer is no, the §4765 path is reconsideration at an open board meeting, and HCD encourages owners who are impeded to contact their city and seek legal counsel.
SB 9 is a different question
SB 9 (2021) lets an owner split a single-family lot and build up to two primary homes on each resulting lot, and it requires cities to approve those projects ministerially. HCD's handbook is careful to say that SB 9 units are primary units, distinct from ADUs and junior ADUs. That distinction decides the HOA question.
Civil Code §4751 protects an ADU or a junior ADU. It says nothing about a lot split or a second primary home, and SB 9 itself (Government Code §65852.21 and §66411.7) does not address private covenants in the parts of the chaptered text we read. The County of Santa Clara states it directly: "SB 9 does not address rules or restrictions implemented and adopted by homeowners' associations or included in CC&Rs." So a CC&R that forbids subdividing a lot, or allows one home per lot, is not voided by SB 9.
Two things are unsettled and we will not pretend otherwise. First, whether a court would ever refuse to enforce a lot-split ban on public-policy grounds is an argument some lawyers make, not settled law. Second, mixed projects are awkward: an SB 9 project that pairs one primary home with an ADU on a parcel puts a protected unit next to an unprotected one. If your plan touches SB 9 inside an HOA, the attorney's review comes before the survey. Our SB 9 guide covers the rest of the law.
The recent bills, and what they change for HOA owners
- AB 1033 (2023, effective 1 January 2024). Lets a city adopt an ordinance allowing an ADU to be sold separately as a condominium. HCD notes that in an existing planned development the owner must first get express written authorization from the association, plus lienholder consent. In practice the HOA holds a real veto over selling the ADU, even though it cannot stop you building it.
- AB 130 (2025, effective 30 June 2025). Added the line in §714.3(b) that reasonable restrictions do not include fees or other financial requirements.
- AB 2533 and SB 1211 (2024, effective 1 January 2025). Neither addresses HOAs. AB 2533 deals with legalizing unpermitted ADUs built before 2020; SB 1211 deals with ADUs on multifamily lots and replacement parking. You will see both cited on HOA pages online, usually loosely.
- AB 3182 (2020, effective 2021). Civil Code §4740 and §4741 allow an ADU or junior ADU in a common interest development to be rented regardless of governing documents that appear to prohibit it.
What to pull from your HOA before a Project Discovery Call
- The recorded CC&Rs and every amendment. You should have received a copy when you bought; the association can supply the current set.
- The architectural guidelines, sometimes called design standards. This is where the material and colour rules live, and it is the document we read first.
- The architectural review application form, with its checklist of the drawings and samples it requires.
- The committee's meeting schedule and its written deadline for a decision. Civil Code §4765 requires prompt deadlines; find out what yours are.
- The annual notice of approval requirements, if you kept it. It tells you which changes the association says need approval.
On the timeline, two clocks matter. The city has 60 days to approve or deny a complete ADU application under Government Code §66317(a), and HCD treats an HOA review that runs past that window as an example of an effective prohibition. Drawing the unit and getting a complete application to the city takes longer than either clock; our guide on how long an ADU takes walks through the full sequence. Running the two reviews in parallel keeps the HOA from adding months on top.
Where this comes up in our counties
In San Jose, many homes in Silver Creek and in parts of Evergreen sit inside homeowners associations, and so do many in Almaden Valley. In San Mateo County the same is true of many homes in Redwood Shores and Foster City. Each association writes its own documents, so we never assume what a given HOA's rules say. We read them.
This guide describes what the statutes and the state housing department's handbook say as of October 2026. It is not legal advice. Whether a specific restriction in your CC&Rs is reasonable is a question for a California attorney who reads your documents.
We build ADUs in Santa Clara and San Mateo counties. On a Project Discovery Call we ask whether the property is in an association and whether you have the architectural guidelines in hand, because those two answers change the sequence before the first drawing exists.
Common questions
Can an HOA ban ADUs in California?
What restrictions can an HOA still place on an ADU?
Does the city need my HOA's approval before issuing an ADU permit?
Can my HOA stop an SB 9 lot split?
Can my HOA stop me from renting my ADU?
Where to go next
Written by the team at Elusive Construction, a licensed California general contractor (B #1112902) building in Santa Clara and San Mateo counties. General information about how residential construction works — not legal advice. For your specific contract, talk to an attorney.
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