Everything homeowners ask about building an ADU in Pasadena — answered with 2026 data.
Yes, ADUs are allowed in All zoning districts that permit single-family or multifamily residential uses, on lots with at least one existing or proposed dwelling (PMC 17.50.275) in Pasadena, CA. The maximum size for a detached ADU is 1,200 sq ft (new construction on single-family lots); limited to 1,000 sq ft in most Hillside Overlay districts. Attached ADUs can be up to 850 sq ft (studio/1-bedroom) or 1,000 sq ft (2+ bedrooms). Pasadena has an ADU-friendliness score of 7/10. Check our full Pasadena ADU rules page for complete zoning details.
ADU construction in Pasadena typically costs $180,000-$400,000. The cost per square foot averages $300-$500. Garage conversions are more affordable at $120,000-$220,000, while prefab ADUs cost $180,000-$300,000. Permit fees add Roughly $5,000-$15,000 total permitting cost depending on size (builder estimates); flat refundable $1,000 Construction & Demolition deposit. Confirm exact figures with Pasadena Permit Center, (626) 744-7311 to your budget. See our detailed Pasadena ADU cost guide.
Detached ADUs in Pasadena can be up to 1,200 sq ft (new construction on single-family lots); limited to 1,000 sq ft in most Hillside Overlay districts. Attached ADUs are limited to 850 sq ft (studio/1-bedroom) or 1,000 sq ft (2+ bedrooms). Junior ADUs (JADUs) have a cap of 500 sq ft. Maximum height is Detached: 18 ft / 2 stories (16 ft in Hillside Overlay, Landmark/Historic districts visible from street, or front-setback Exemption ADUs); +2 ft within 1/2 mile of major transit to match primary roof pitch. Attached: up to 25 ft / 2 stories. You are allowed up to Single-family lots: 1 ADU + 1 JADU. Multifamily lots: conversion ADUs up to 25% of existing units + 2 detached ADUs (SB 1211 may allow up to 8 detached on multifamily lots — state law prevails over local cap) on a qualifying lot.
Rear setback: 4 ft for new construction; none for conversions of existing structures. Side setback: 4 ft for new construction; none for conversions; 6 ft eave-to-eave building separation for non-exemption detached ADUs. Front setback: Underlying zone front setback applies, except for 800 sq ft Exemption ADUs. Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
1 space per unit or per bedroom (whichever is less); waived within 1/2 mile of transit, in historic districts, for conversions within existing structures, or with car share within a block — most Pasadena lots qualify for a waiver. Many cities and states have been relaxing ADU parking requirements in recent years. In California, no additional parking is required for ADUs near transit.
Not required for ADUs. JADU owner-occupancy removed by AB 1154 (eff. Jan 1, 2026) where the JADU has separate sanitation facilities; still applies to shared-bath JADUs. Note that owner-occupancy rules vary by state law — California and several other states have eliminated this requirement for standard ADUs.
The ADU permit review timeline in Pasadena is typically 60-day ministerial review; deemed approved if the city fails to act within 60 days (SB 543, eff. Jan 1, 2026). The plan check process takes approximately 50% plan check fee reduction for Standard Plans or affordability agreements; ~25% overall permitting cost reduction for most ADUs up to 900 sq ft (May 2025 fee package). Pre-approved plans availability: Paused — the city's ADU Standard Plans expired Dec 31, 2025 due to California Building Code updates. Since Jan 1, 2026 the 5 free city designs (374-750 sq ft) may only be used on properties red-tagged in the Eaton Fire; the city is evaluating new plans.
Average ADU rental income in Pasadena: 1-bedroom units rent for $2,200-$2,900/mo/month, 2-bedroom units for $3,200-$3,700/mo/month. Short-term rentals: No — ADUs/JADUs legally created on or after Jan 1, 2017 must be rented for terms longer than 30 days. Expected ROI: 5-8% annual return.
The minimum lot size for an ADU in Pasadena is None for ADUs under state-mandated pathways. This applies to detached ADUs — garage conversions and JADUs may have different or no lot size requirements.
Garage conversions are one of the most popular and affordable ADU options. In Pasadena, a garage conversion typically costs $120,000-$220,000. The key advantages are lower cost (no foundation work), potential setback exemptions, and faster permitting. Read our complete garage conversion guide.