Manhattan Beach ADU: Regulations, Costs & Permits

• State law only, for now: the city's 2025 ADU rules for the Coastal Zone are waiting on California Coastal Commission certification. Until then, Coastal Zone ADUs are reviewed against state ADU law, not the local code.
• A Coastal Development Permit is required: the local coastal program's exemption for single-family improvements doesn't cover second units, so ADUs need a CDP in addition to the building permit. CDPs are discretionary and filed as a Planning Entitlement through the city's online portal.
• Appealable areas: parts of the Coastal Zone are appealable to the Coastal Commission. For minor projects, the hearing can be waived if no one requests one within 15 working days of notice.
• Parking: the usual no-replacement-parking rule has a Coastal Zone exception, and the main house's required parking has to be kept.

• Building permit only: ADUs that meet state minimums (for example a detached unit up to 800 sq ft with 4 ft side and rear setbacks) go straight to building permit with no local standards. JADUs follow this path too.
• ADU Permit: everything else gets a ministerial ADU Permit, with no hearing, reviewed alongside the building permit.
• Units per lot on the ADU Permit path: up to two ADUs plus a JADU on a single-family lot, with only one of them detached.

• ADU Permit size: 850 sq ft for a studio or one-bedroom, 1,000 sq ft for two bedrooms. A new attached ADU can't exceed 50% of the home's buildable floor area. None of these limits can push an ADU below 800 sq ft.
• Floor area: ADU Permit units count toward the lot's maximum buildable floor area, unless that would block an 800 sq ft unit. State-minimum ADUs don't count.
• Detached height: 16 ft, or up to 26 ft when the ADU sits directly above or below a detached garage. On Manhattan Beach's narrow lots, stacking over a garage is often the best fit.
• Attached height: up to 25 ft on the ADU Permit path.

• Setbacks: 4 ft side and rear, the front setback matches the house, and none for conversions or same-footprint rebuilds. Detached ADUs need 5 ft from other buildings.
• Alley lots: if your lot backs onto an alley, any new driveway for the ADU must come off the alley.
• Second-story privacy: on non-alley lots, openings on a second-story detached ADU within 12 ft of the rear line or 10 ft of an interior side line need translucent glazing that's fixed or at least 5 ft above the floor.
• Decks: none higher than 30 inches in the main house's required yards, apart from minimum landings.
• Basics: a permanent foundation, separate exterior access, and a kitchen with a permanent stovetop.
• Guest houses: if a lot has both a guest house and an ADU, one of them must be attached to the main house, unless the project fully meets state minimums.

In residential Area Districts I and II, protected trees in the 20 ft front setback and 5 ft corner-side setback need a Tree Permit to remove or relocate. Building on a lot with a protected tree requires a Tree Permit alongside the building permit and an ISA-certified arborist report before plan check. Removal permits start at $100, and trimming permits at $83.

• Utility letters first: before the ADU Permit (or the building permit, if no ADU Permit is needed), you submit water and sewer availability letters to the Building Official.
• Online portal: CDPs, planning entitlements, and tree permits go through the city's Citizens Self Service portal as unlocked, labeled PDFs.
• Address: a change of address application is part of ADU plan check.
• Water and sewer: the city's Utilities Division supplies water from city wells, West Basin, and Metropolitan Water District. You own the sewer lateral, and wastewater goes to LA County Sanitation Districts.
• Impact fees: none under 750 sq ft under state law, and proportional fees above that.
• Legalizing an older unit: unpermitted ADUs built before 2020 can be legalized under state law.

• Parking on the ADU Permit path: one space per ADU, with the usual exceptions such as within half a mile of transit. Tandem and setback parking are allowed. JADUs need no parking.
• Rentals: 30 days or longer for ADUs and JADUs.
• JADUs: 150 to 500 sq ft inside the house or attached garage, with a recorded covenant for owner occupancy, 30-day rentals, and no separate sale.
• Sprinklers: not required in the ADU unless the house requires them.

Do I need a Coastal Development Permit for an ADU in Manhattan Beach?

Yes, if your lot is in the Coastal Zone. The city's coastal program doesn't exempt second units, so a CDP is needed alongside the building permit. Check your lot on the city's interactive map.

How tall can an ADU be in Manhattan Beach?

A detached ADU is 16 ft, or up to 26 ft when it sits directly over or under a detached garage. Attached ADUs can reach 25 ft.

How big can an ADU be in Manhattan Beach?

On the ADU Permit path, 850 sq ft for a studio or one-bedroom and 1,000 sq ft for two bedrooms. A unit that meets state minimums can be up to 800 sq ft detached, with no local standards.

Can I short-term rent a Manhattan Beach ADU?

No. ADUs and JADUs must be rented for 30 days or longer.

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