California ADU rules · San Mateo County
Can I Build an ADU in East Palo Alto?
Yes — you can build an ADU in East Palo Alto. California's statewide ADU law requires every city, including East Palo Alto, to approve a qualifying accessory dwelling unit by right, plus a junior ADU (JADU) on a single-family lot. What varies city to city are the local specifics below.
Can you build one?
ADUs allowed
CA state lawYes — by right
ADUs and JADUs are allowed by right in all residential and mixed-use zones; ministerial approval, no hearing.
Units on a single-family lot
Local rule1 ADU per lot (local code); state override allows 1 ADU + 1 JADU
Local code allows only 1 ADU per lot; state law preempts to allow 1 ADU + 1 JADU.
Units on a multifamily lot
CA state lawConversion ADUs (≥1, up to 25% of units) + up to 8 detached
Conversions of non-livable space (at least 1, or up to 25% of existing units) plus up to 8 detached ADUs on a lot with existing multifamily — never exceeding the number of existing units. JADUs are single-family only.
Junior ADU (JADU)
CA state lawAllowed
Up to 500 sq ft, within the walls of an existing single-family home (single-family lots only).
Size & height
Max detached ADU size
Local rule1,000 sq ft
Detached ADUs: 700 sq ft max, increased by 1 sq ft per 10 sq ft of lot area over 6,500 sq ft, up to 1,000 sq ft.
Max attached ADU size
Local rule50% of primary, not to exceed 1,000 sq ft
Attached ADUs limited to 50% of primary dwelling, max 1,000 sq ft.
Guaranteed minimum size
CA state law800 sq ft
An 800 sq ft ADU must be allowed regardless of FAR/lot-coverage caps; a city also cannot cap an attached ADU below 850 sq ft (1,000 for 2+ bedrooms).
Max JADU size
CA state law500 sq ft
Max height
CA state law16 ft
16 ft baseline; cities must allow 18 ft within ½ mi of a major transit stop or where the primary dwelling is two-story, and 20 ft on a lot with a multistory multifamily building.
Setbacks
Side setback
Local rule3 ft
3 ft side setback for detached ADUs on interior lots; 12 ft on street side for corner lots.
Rear setback
CA state law4 ft
Front setback
CA state lawNo front setback may block the mandatory 800 sq ft / 16-ft / 4-ft-setback ADU; otherwise per base zone
Separation from main house
Local rule6 ft
Detached ADUs must be set back 6 ft from the existing house.
Parking
Parking required
Local ruleUp to 1 space
One uncovered off-street parking space required for the ADU, in addition to main dwelling parking.
Transit parking exemption
CA state lawYes — no parking required near transit & for conversions
No parking may be required within ½ mi walking distance of transit, in a historic district, for an ADU within an existing structure, within one block of car-share, or in certain permit-parking areas.
Garage-conversion replacement parking
CA state lawNot required
When a garage/carport is demolished or converted to build an ADU, replacement parking cannot be required.
Approval, timeline & cost
Approval path
CA state lawMinisterial (by right)
No public hearing or discretionary design review for a qualifying ADU.
Approval timeline
CA state law60 days
The agency must act within 60 days of a complete application — and the ADU is deemed approved if it does not.
Owner-occupancy
Local ruleOnly for a JADU
Local code recites an owner-occupancy requirement, but California Gov. Code § 66315 bars owner-occupancy requirements for ADUs — enforceable for JADUs only. Verify the JADU covenant with the city.
Impact-fee waiver
CA state lawWaived under 750 sq ft
An ADU of 750 sq ft or less pays no impact fees (the 750 sq ft threshold itself is exempt under § 66311.5); larger ADUs pay fees proportional to the primary dwelling. JADUs (≤ 500 sq ft) are exempt.
Permits required
CA state lawBuilding permit
Only a ministerial building permit — no conditional use permit or discretionary design review for a qualifying ADU.
East Palo Alto-specific factors that can change the answer
State law sets the floor, but these local conditions often decide whether a specific parcel works.
Historic properties
ADUs may be restricted or prohibited on properties listed in the California Register of Historic Places.
Fire code compliance
ADUs must comply with applicable building, health, and fire codes; no sprinklers required if not required for primary residence.
East Palo Alto sets a local detached ADU maximum of 1,000 sq ft (with lot size formula), requires 3 ft side and 6 ft rear setbacks, and mandates a 6 ft separation from the main house. Owner-occupancy and 120-day review are in local code but preempted by state law.
Frequently asked questions
Can I build an ADU in East Palo Alto?
Yes. California's statewide ADU law requires East Palo Alto to approve a qualifying accessory dwelling unit ministerial (by right), plus a junior ADU (JADU) on a single-family lot.
How big can an ADU be in East Palo Alto?
A detached ADU of at least 1,000 sq ft must be allowed, and an ADU of 800 sq ft can never be zoned out by floor-area or lot-coverage limits. A JADU can be up to 500 sq ft.
What are the setback requirements for an ADU in East Palo Alto?
Side and rear setbacks are limited to 3 ft. No front setback may block the mandatory 800 sq ft / 16-ft / 4-ft-setback ADU; otherwise per base zone.
Is parking required for an ADU in East Palo Alto?
Up to 1 space. No parking can be required within ½ mile of transit, for conversions, or for units inside the primary home. When a garage is converted, replacement parking is not required.
How long does ADU approval take in East Palo Alto?
A complete application must be acted on within 60 days, with ministerial (by right) — no public hearing or discretionary design review for a qualifying ADU.
Do I have to live on the property to build an ADU in East Palo Alto?
Owner-occupancy: only for a jadu. ADUs under 750 sq ft are also exempt from impact fees.
Sources
- East Palo Alto Development Code, Title 18, Chapter 18.96 (August 2018)
- § 18.96.030
- § 18.96.040(D)
- § 18.96.040(M)
- § 18.96.040(G)
- § 18.96.050
- § 18.96.010(C)
- § 18.96.040(E)
- Cal. Gov. Code §§ 66310–66342 (ADU Law)
- HCD 2025 Accessory Dwelling Unit Handbook
- Cal. Gov. Code § 66317 (ministerial approval, 60-day deadline)
- Cal. Gov. Code § 66323 (by-right ADU/JADU, 800 sq ft, 4-ft setbacks)
- Cal. Gov. Code § 66333 (junior ADUs)
- Cal. Gov. Code § 66321 (size minimums & height)
- Cal. Gov. Code § 66322 (ADU parking; § 66334 covers JADU parking)
- Cal. Gov. Code § 66314 (local ordinance standards)
- Cal. Gov. Code § 66311.5 (impact fees: none for an ADU ≤ 750 sq ft or JADU ≤ 500 sq ft)
Last updated August 2018. This is an AI-assisted summary of East Palo Alto's ADU rules, drawn from its published ordinance and California ADU law — general information, not legal advice, and it may be incomplete or out of date. Verify the controlling rule for your specific parcel with East Palo Alto Planning before relying on it.
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