ADUs in Carmel-by-the-Sea, Carmel and Pebble Beach: what you can build, and who decides
An accessory dwelling unit (ADU) can house family, a caregiver, or a long-term tenant, and buyers ask about them all the time. State law now requires cities and counties to approve qualifying ADUs without a hearing, but here the rules still depend on which side of a line you’re on: the town, the county’s coastal zone, or Pebble Beach’s private architectural review. Here’s where things stand in November 2026.
The short version: California requires local agencies to approve qualifying ADUs ministerially, including one ADU and one junior ADU inside an existing home and a detached ADU of up to 800 square feet with four-foot side and rear setbacks. Carmel-by-the-Sea is processing ADUs under state law while it updates its 2017 ordinance, and its coastal protections still apply. In the Carmel area and Pebble Beach, Monterey County’s new coastal ADU ordinance took effect December 19, 2025, and the coastal zone requires a coastal administrative permit. Pebble Beach adds its own architectural review. Everywhere, check water with MPWMD first, and plan on rentals of more than 30 days: ADUs can’t be short-term rentals.
Detached ADU
State law guarantees at least this, with 4-ft side and rear setbacks.
Review time
A complete ADU application is deemed approved if not acted on.
Carmel-by-the-Sea projects
Approved in design review with an ADU, Feb 2021 – Aug 2026 (my count).
Rentals
ADUs can’t be used as short-term rentals.
What state law guarantees
California’s ADU law sets a floor that cities and counties can’t go below, and it has changed almost every year since 2019.
Inside the house
One ADU and one junior ADU (JADU) per lot within the existing or proposed space of a single-family home or an existing accessory structure, with up to 150 square feet of expansion for getting in and out.
A detached unit
One new detached ADU with four-foot side and rear setbacks. The local agency may cap it at 800 square feet of livable space and limit its height.
Junior ADUs
A JADU sits entirely within a single-family home, is no more than 500 square feet, has an efficiency kitchen, and may share a bathroom with the main house.
Timing and owner rules
A complete application is deemed approved if the agency doesn’t act within 60 days. Local agencies can’t require the owner to live on the property for an ADU, and in common-interest developments, CC&Rs that effectively prohibit or unreasonably restrict ADUs on single-family lots are void.
Older unpermitted units
For an unpermitted ADU built before January 1, 2020, an agency can’t deny a permit to legalize it over building code violations unless fixing them is needed for health and safety.
The coastal exception
State ADU law expressly preserves the California Coastal Act. Much of Carmel-by-the-Sea, the Carmel area and Pebble Beach is in the coastal zone, which is why local coastal rules still matter.
Gov. Code 66323 HCD ADU resources HCD letter to the city, Oct 2025
Carmel-by-the-Sea: state law now, a new ordinance in progress
The city’s rules are being rewritten. Confirm the current process with the planning department before you design.
Where it stands
The city’s ADU ordinance on file with the state dates to 2017. In October 2025, the state housing department wrote that it may be out of date with state law. The city says ADUs and JADUs are still permitted in the meantime under state law, and held a Planning Commission workshop on a draft ordinance in September 2025 and a City Council policy discussion in August 2026.
What still applies
City staff told the council that coastal protections in the city’s certified Local Coastal Program, such as floor area, setbacks, tree protection and historic preservation, continue to apply, with flexibility where there’s no coastal conflict. A coastal development permit may be needed.
Water first
The city asks owners to check with MPWMD before anything else, because an ADU needs a kitchen sink and a bathroom (sink, toilet, and shower or tub).
It’s happening
From my own count of city design review records, 14 of 62 building projects approved in design review between February 2021 and August 2026 included an ADU.
See also Carmel-by-the-Sea building permits, tree permits and historic home rules. Design review counts are from my Carmel-by-the-Sea market stats page.
City ADU ordinance status Aug 4, 2026 council packet (ADU discussion)
The Carmel area and Carmel Valley: Monterey County rules
Carmel Point, Carmel Meadows, Hatton Fields, Carmel Woods, Jacks Peak and the other neighborhoods around the town mostly follow county rules.
New coastal ordinance
The county adopted a new coastal-zone ADU and JADU ordinance, effective December 19, 2025, updating the Carmel Area Land Use Plan and the coastal zoning code to match state law. The county said it would give more guidance on the permit process in early 2026.
Coastal permit
The county says a coastal administrative permit is required for an ADU in the coastal zone. Inland, an ADU is generally an allowed use, but design approval, tree removal or other factors may apply.
Size and setbacks
The county’s ADU FAQ, citing its inland code, says an existing structure may be converted to an ADU, and a new ADU may keep a four-foot side setback and a height of up to 16 feet, with exceptions if standards would prevent at least an 800-square-foot unit.
Septic and wells
Where there’s no sewer, the county says most properties under 1.25 acres on septic will need an alternative septic system with extra treatment to add an ADU. Wells also route the application through Environmental Health.
Pre-designed plans
The county offers three pre-designed ADU plans: one bedroom (515 square feet), two bedrooms (749) and three bedrooms (1,200), each submitted for normal review.
Which side of the line?
The mailing address says Carmel either way. See buying a home in Carmel and Carmel vs Carmel-by-the-Sea vs Carmel Valley.
Pebble Beach: county rules plus architectural review
Del Monte Forest homes answer to Monterey County and to Pebble Beach Company’s Architectural Review Board.
One-house lots
The ARB standards say most Del Monte Forest properties are limited to one single-family use, and an additional ADU may be allowed only if the unit and its use meet all state and county rules.
Height and paperwork
ADUs can’t exceed 16 feet in height under the ARB standards (other accessory structures, 15 feet), and an ADU application must include a copy of the original grant deed with its CC&Rs.
County coastal permit
Pebble Beach is in the coastal zone, so the county’s coastal ADU rules and coastal administrative permit apply too.
Start with both
Talk to the ARB and the county before you hire an architect. See building or remodeling in Pebble Beach.
The step that stops most projects: water
Every jurisdiction here sends you to the Monterey Peninsula Water Management District.
A water permit
MPWMD requires a water permit whenever new fixtures are added or a new water use is created, including remodels and additions. An ADU’s kitchen and bathroom add fixtures.
Credits and entitlements
Whether you can add fixtures depends on the water available to your property. See water credits on the Monterey Peninsula.
An ADU is for long stays, not weekends
State rule
For ADUs approved under the state’s guaranteed-approval path, the local agency must require rentals longer than 30 days.
County rule
Monterey County says ADUs can’t be used as short-term rentals, and its vacation-rental rules exclude ADUs and JADUs.
In town
Carmel-by-the-Sea already requires stays of 30 days or more in its single-family district. See Carmel-by-the-Sea rental rules.
Monthly and long-term
That leaves monthly and long-term tenants, family, or a caregiver. I co-own Peninsula Luxe, which manages monthly and long-term rentals.
Buying or selling a home with an ADU or guest unit
A “guest house” in a listing isn’t always a permitted ADU.
Was it permitted as an ADU?
Ask for the building permit and final. A guest house, studio or pool house may be permitted without a kitchen, and adding one later is a new ADU application.
Water and fixtures
Compare the fixtures on site with MPWMD’s records. An open water permit or extra fixtures can mean work to resolve before or after closing.
Rental history and leases
If the unit is rented, get the lease. Short stays may not have been allowed; long-term tenants may have rights that survive the sale.
Document it
If you’re selling a home with an ADU, gather permits and water records before you list. A documented, legal unit is easier to value and to sell. See home selling tips.
Thinking about a home with room for family?
I’ll check whether a guest unit is legal, what the water and permit records say, and whether an ADU is realistic on a lot before you’re committed.
Start with a 30-minute call. No pitch.
Buying in Carmel-by-the-SeaBuying in CarmelBuying in Pebble Beach
Let’s look at the lot
Call or text 831-747-0310, or book a 30-minute call.
Before you rely on this
- ADU law changes often. State rules are from Government Code 66323 and HCD’s October 8, 2025 letter to the city; city status from the city’s long-range planning page and the August 4, 2026 council packet; county rules from the county’s ADU pages, all checked Nov 3, 2026.
- Carmel-by-the-Sea is updating its ADU ordinance; confirm the current process with the Community Planning and Building Department (831-620-2010) before you design.
- Pebble Beach ARB standards are from the Del Monte Forest Architectural Standards and Residential Guidelines (April 2022 edition) as fetched Nov 3, 2026.
- This is general information, not legal advice. Whether a specific lot can add an ADU depends on zoning, coastal rules, water, septic and deed restrictions.
ADUs: quick questions
Can I build an ADU in Carmel-by-the-Sea?
Generally yes. The city says ADUs and JADUs are permitted under state law while it updates its 2017 ordinance, and its coastal protections, such as floor area, setbacks, tree protection and historic preservation, still apply. Check water with MPWMD first and confirm the process with the planning department.
How big can an ADU be in Carmel or Pebble Beach?
State law guarantees at least a detached 800-square-foot ADU with four-foot side and rear setbacks. Monterey County’s ADU FAQ says a new ADU may be up to 16 feet tall with a four-foot side setback, and Pebble Beach’s ARB caps ADU height at 16 feet.
Do I need a coastal permit for an ADU?
Often. Monterey County requires a coastal administrative permit for ADUs in the coastal zone, and Carmel-by-the-Sea may require a coastal development permit.
Can I rent my ADU on Airbnb?
No. Monterey County says ADUs can’t be short-term rentals, state law requires rentals of more than 30 days for ADUs approved on the guaranteed path, and Carmel-by-the-Sea requires stays of 30 days or more in its single-family district.
Do I need a water permit for an ADU?
Yes, if you add fixtures. MPWMD requires a water permit whenever new water fixtures are added or a new water use is created.
Does Pebble Beach allow ADUs?
Sometimes. Most Del Monte Forest lots are limited to one single-family use, but an ADU may be allowed if it meets state and county rules. The ARB caps ADU height at 16 feet and requires the original grant deed with CC&Rs in the application.
Do I have to live on the property to have an ADU?
No. State law bars local agencies from requiring owner occupancy for an ADU.
Is a guest house the same as an ADU?
Not necessarily. A guest house or studio may be permitted without a kitchen. Adding a kitchen to make it an ADU is a new application, and it needs a water permit.
How long does ADU approval take?
A complete application is deemed approved if the agency doesn’t act within 60 days, but coastal permits and water permits can add time.
Updated November 2026 · Facts checked Nov 3, 2026 against Government Code 66323, HCD, the City of Carmel-by-the-Sea, Monterey County, MPWMD, and the Del Monte Forest ARB standards
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