ADU Rules in Irvine, CA (2026)

Irvine, CA permits accessory dwelling units (ADUs) on residential properties. ADUs — also called granny flats, in-law units, backyard cottages, or secondary suites — are secondary housing units on a single-family or multifamily lot. California state law actively preempts local restrictions, making ADU approval a streamlined ministerial process. In Irvine, the Irvine Community Development Department — Building and Safety Division handles ADU permit applications. Below you will find the current size limits, setbacks, fees, and timeline for building an ADU in Irvine.

ADU Size Limits

ADU Size Limits in Irvine: Detached ADU: size varies by zoning — see official source (max height: varies — see official source). Attached ADU: 50 percent of the existing primary dwelling. Junior ADU (JADU): up to 500 sq ft — must be within the existing primary dwelling or accessory structure.

Permit Fees

ADU Permit Fees in Irvine: Plan check fee: $600–$3,500. Building permit fee: $1,200–$5,000 depending on valuation. Impact fees: None. School fees: Exempt for ADUs under 500 sqft. ADUs 500+ sqft subject to Irvine Unified School District developer fees.. Total estimated permit cost: Varies.

Permit Timeline

Irvine ADU Permit Timeline: The permitting agency shall either approve or deny the application to create or serve an accessory dwelling unit within 60 days from the date the permitting agency receives a completed application if there is an existing single-family or multifamily dwelling on the lot. Apply through the Irvine Community Development Department — Building and Safety Division online permit portal. Phone: (949) 724-6000.

Setback Requirements

ADU Setback Requirements in Irvine: Front setback: follows zone standard. Side setback: 4 feet. Rear setback: 4 feet.

Parking Requirements

Parking Requirements: No additional parking required for ADUs within one-half mile of Irvine Metrolink/Amtrak station or OCTA bus rapid transit routes. No replacement parking when garage converted to ADU. Per California Gov Code §66322(a)(1) and §66314(d)(11) (Stats. 2024 Ch. 7 §20).

Restrictions & Requirements

• •ADU must comply with objective standards in Irvine City Code Section 2-5-8
• •HOA Architectural Review Committee may review exterior design elements for compatibility with Planned Community design standards — but cannot prevent ADU construction
• •ADU cannot be sold separately from primary dwelling
• •Short-term rental of ADU requires Irvine STR registration (Irvine had an STR ban through 2022 — check current ordinance)
• •ADU must have permanent foundation
• •Irvine Ranch Water District connection fees apply for new utility service

How Many ADUs Are Allowed?

Number of ADUs Allowed in Irvine: Single-family lots: 1 ADU + 1 JADU per single-family lot. Multifamily properties: Up to 25% of existing units (minimum 2) as detached ADUs; non-livable space conversions by-right per state law. Irvine's master-planned communities have larger lot sizes than many Orange County cities — a typical Irvine SFR has 5,000-8,000 sqft lot, leaving room for both an ADU and JADU. UCI campus proximity drives strong rental demand.

Single-Family Lots

1 ADU + 1 JADU per single-family lot

Multifamily Properties

Up to 25% of existing units (minimum 2) as detached ADUs; non-livable space conversions by-right per state law

Statewide Preemption

State Law & Preemption

Frequently Asked Questions