Most residential permit questions in California come down to what a reviewer is willing to accept. Accessory dwelling units are the exception: the state took the discretion out of the review, put deadlines on the agency, and left the homeowner in an unusually strong position. Then it left one thing alone. On the coast a separate permit system sits underneath all of it, untouched. This post is about that machinery — what ministerial review buys you, what the clocks oblige an agency to do, and why a unit that is by right on paper can still wait on a coastal development permit.
Citations below use the current numbering, Government Code §§66310–66342; §65852.2 is superseded. Whether your project is an ADU at all, rather than a JADU or an addition, is settled in what qualifies as an ADU in California.
What ministerial approval changes for you
ADU applications are reviewed ministerially (§§66317(a), 66335(a)). Three things are off the table: a public hearing, discretionary review, and any body deciding whether the massing suits the street.
Be precise about what that is worth, because it is routinely oversold. Ministerial review does not mean nobody reads the drawings. It means the reviewer applies objective standards and issues the permit when the set meets them. Taste is not an input, and neither is neighbor opposition. Instead of a hearing you get corrections — a list of where the drawings fail a standard, answered with revisions rather than with argument.
That inversion is the real shift in the homeowner’s position. In a discretionary process you are persuading someone; in a ministerial one you are demonstrating compliance, and the burden of naming a defect moves onto the agency. The strength of your application becomes purely a drafting question — no charm offensive available, and none needed.
Paired with it is the by-right category at §66323(a)(2): one detached new-construction ADU of up to 800 square feet with four-foot side and rear setbacks, which local development standards do not get to block, though a local agency may still apply a height limit — generally 16 feet detached, or 18 feet within half a mile of a major transit stop. Outside that envelope the unit is measured against the local ordinance instead. Both routes stay ministerial — only the ruleset changes.
The two clocks, and what happens when one runs out
Ministerial review comes with statutory deadlines rather than a queue position:
- Clock one — 15 business days. The window in which the agency decides whether what you filed is a complete application.
- Clock two — 60 days. Approve or deny. It runs only from the moment completeness is established, never from the filing date.
The order is what trips people. The first clock is not a review of your design; it checks whether the submittal contains what the jurisdiction requires before review can begin. Only when that check comes back complete does the 60-day decision clock start. An incomplete submittal never starts it — it produces a letter naming what is missing, and on resubmittal the completeness review begins again from the top. Two thin submittals cost more calendar than one thorough one, the same arithmetic that governs California building permit requirements generally.
What if an agency lets a clock pass? The statute answers that directly. Miss the 15 business days and the application is deemed complete; miss the 60 days and the application is deemed approved (§66317). That is a materially stronger position than most homeowners realize. Keep a dated submittal receipt and put any follow-up in writing, citing the filing date — how a deemed approval is administered in practice still varies by jurisdiction, and a documented trail is what makes it usable.
Owner-occupancy: permanent for ADUs, conditional for JADUs
No owner-occupancy requirement may be imposed on an ADU (§66315). Treat this as settled rather than as a current allowance: an earlier version carried a sunset that would eventually have let local occupancy rules return, and that sunset was removed. The prohibition is permanent. You need not live on the property to build the unit, or to rent it — though a local agency may still require that rentals be 30 days or longer. That is what makes an ADU workable as an income project rather than only as a family arrangement.
JADUs sit differently, for a structural reason rather than a political one. A JADU may share sanitation with the primary residence, so it is not fully independent, and where that sharing exists owner-occupancy may be required (§66333). JADU rentals must also exceed 30 days. If the plan is to rent and live elsewhere, that distinction decides which unit is worth drawing.
Parking: usually none, and it changes the site plan
Parking used to be the quiet project-killer on small lots: a required space consumes site area before the unit is placed. The ceiling is now one space per unit or per bedroom, whichever is less, and none at all may be required where the ADU is:
- part of the existing primary residence or an accessory structure;
- sited in an architecturally and historically significant historic district;
- sited within a half mile walking distance of transit; or
- sited where on-street parking permits are required but are not offered to the ADU’s occupant.
Units in the by-right category owe nothing at all. Stack the exemptions against the housing stock on the Monterey Peninsula — older, walkable, much of it near transit or inside historic districts — and a great many parcels here owe nothing. Establish this in week one: the answer decides how much of the lot you actually have to work with.
The coastal zone: the ADU statute stops where the Coastal Act begins
Everything above is the favorable half of the story. Here is the half that sets schedules on this coastline, and the half most general ADU writing skips.
Section 66329 does two things at once: it extends ADU law into the coastal zone, and in the same breath it declines to alter or lessen the Coastal Act. Summaries reliably report the first half and drop the second, which is how homeowners arrive at a design meeting believing streamlining solved a problem it never touched. The consequence: a coastal development permit can still be required for an ADU, and ministerial review does not waive it.
Why these are two questions, not one
Set the by-right category against the CDP and the logic comes clear. A unit can be fully by right under §66323 — ministerially approvable, immune from local setback and parking standards, unreviewable on aesthetics — and still require a coastal development permit, because the CDP does not arise from ADU law at all. It arises from the Coastal Act and the local coastal program governing the parcel, and the ADU statute declines to reach into either. Whatever discretion the coastal review carries, it keeps.
The two reviews are parallel tracks, not a sequence. Clearing one does not clear the other, and the coastal track sets the outside date. One borrowed protection applies: on an ADU coastal permit application the local agency is held to a 60-day deadline to act. That limits how long the coastal review may take. It does not mean the permit can be skipped, and it is the most commonly misread sentence in the whole subject.
What this looks like on the Monterey Peninsula
Coastal status is the first question on an ADU here, not a late complication. Parcels in Carmel, in Pebble Beach and along the coastal edges of Monterey sit inside the coastal zone, and whether a CDP is required turns on the parcel and the local coastal program applying to it. That is not an answer to infer from any general article, this one included; it comes from the planning department, on your address.
Pebble Beach adds a layer with no connection to state law. As unincorporated county in the Del Monte Forest, projects there run dual approval through the Pebble Beach Company Architectural Review Board and Monterey County. ADU streamlining does not displace that either — count it as its own review rather than folding it into the county’s.
So confirm coastal zone status and CDP applicability before design decisions get made, because coastal siting considerations can move a unit on the lot after a floor plan is already resolved. The expensive version of this project is the one where a straightforward 800 square foot unit gets drawn first and asked about second.
The draft guidance, and what it does not yet do
There is movement worth tracking. The Coastal Commission and the Department of Housing and Community Development are under a statutory direction to issue guidance that would make it easier for a jurisdiction to amend its local coastal program for ADUs, and draft guidance was published April 13, 2026. Among the mechanisms it discusses is the Categorical Exclusion Order, an instrument that would let a jurisdiction lift the CDP requirement from defined classes of low-impact ADUs.
Note what that is and is not. It is a draft; it describes something jurisdictions may pursue rather than something they hold; and it would operate jurisdiction by jurisdiction, not statewide. Nothing in it changes what your local coastal program requires today, so design to the rule in force rather than the one in circulation.
Requirements and timelines described here were researched in September 2026 and are typical rather than guaranteed. Verify current requirements with the building department for your jurisdiction.
What this post deliberately does not cover
Three adjacent questions are answered properly elsewhere. What a permit-ready plan set contains, sheet by sheet, and what a garage or existing-space conversion takes to bring up to code are both on our ADU design page. Whether your project qualifies as an ADU, a JADU or neither is answered in what qualifies as an ADU in California.
RDD Solutions works out of Carmel, drafting permit sets for homeowners and general contractors from Monterey County into Santa Cruz County. We design and draft. We do not build, and we are not an architecture firm — what we hand over is the set your jurisdiction reviews and your builder works from.
Frequently asked questions
What does ministerial approval actually get me on an ADU?
It removes discretion from the review: no public hearing, no discretionary review, no design body weighing in on appearance (§§66317(a), 66335(a)). The reviewer applies objective standards and issues the permit when your set meets them, so the question stops being whether officials like the project and becomes whether the drawings demonstrate compliance.
Can my ADU be denied because a neighbor objects or because of how it looks?
Not through the ADU review. Objective standards decide it, so opposition and aesthetic judgment are not inputs, and a denial has to name a standard the application fails. That protection covers the ADU approval specifically — a separate review, such as a coastal development permit or Pebble Beach Company architectural review, runs under its own rules.
What happens if the agency misses the 15-business-day or 60-day deadline?
The statute attaches a consequence to each. The first, 15 business days, is for deciding whether what you filed counts as complete — miss it and the application is deemed complete. The second, 60 days, is for the decision itself and runs only once completeness is established — miss it and the application is deemed approved (§66317). Follow up in writing citing your filing date; how a deemed approval is administered still varies by jurisdiction, and a dated paper trail is what makes it usable.
If my parcel needs a coastal development permit, does that replace the ADU approval?
No. The two run in parallel and neither substitutes for the other. Section 66329 extends ADU law into the coastal zone without altering or lessening the Coastal Act, so the coastal permit is issued under a separate body of law and keeps whatever discretion the local coastal program gives it. One timing protection applies: the agency is held to 60 days to act on that application.
Are the coastal categorical exclusions for ADUs available yet?
Not as something to rely on. Draft guidance published April 13, 2026 discusses Categorical Exclusion Orders as a mechanism a jurisdiction could pursue to lift the CDP requirement from certain low-impact ADUs. That is a draft describing an option, taken up jurisdiction by jurisdiction rather than statewide, so plan against the requirement that exists today.
Working out what your parcel allows
Tell us where the property is and what you want the unit to do. We will tell you whether the coastal zone is in play and what the approval path looks like from there. See our ADU design services, or get in touch.