Everything homeowners ask about building an ADU in Torrance — answered with 2026 data.
Yes, ADUs are allowed in Any residentially zoned or mixed-use lot with a proposed or existing dwelling (single-family or multifamily) in Torrance, CA. The maximum size for a detached ADU is 1,000 sq ft (800 sq ft under the state-exempt ministerial path); accessory-structure conversions exempt from the cap. Attached ADUs can be up to 1,000 sq ft; must share at least 25% of linear wall with the primary dwelling. Torrance has an ADU-friendliness score of 5/10. Check our full Torrance ADU rules page for complete zoning details.
ADU construction in Torrance typically costs $200,000-$380,000. The cost per square foot averages $250-$400. Garage conversions are more affordable at $70,000-$160,000, while prefab ADUs cost $120,000-$280,000. Permit fees add Fee assessed at building-permit application covering plan review, permit processing, and development impact mitigation — confirm amounts with Community Development, (310) 618-5990 to your budget. See our detailed Torrance ADU cost guide.
Detached ADUs in Torrance can be up to 1,000 sq ft (800 sq ft under the state-exempt ministerial path); accessory-structure conversions exempt from the cap. Attached ADUs are limited to 1,000 sq ft; must share at least 25% of linear wall with the primary dwelling. Junior ADUs (JADUs) have a cap of 500 sq ft within the primary dwelling or attached garage (+150 sq ft enclosed staircase allowance for 2nd-story JADUs). Maximum height is Detached: 18 ft one-story / 23 ft two-story citywide; 16 ft in Hillside Overlay and Coastal Zone; attached: 18 ft one-story / 25 ft two-story; interior height capped at 12 ft (one-story) / 22 ft (two-story). You are allowed up to Single-family: 1 ADU + 1 JADU; existing multifamily: interior conversions up to 25% of units (min. 1) plus up to 8 detached ADUs (not exceeding existing unit count, 800 sq ft each); proposed multifamily: 2 detached. Coastal Zone parcels also need a Coastal Development Permit, waiver, or exemption from the California Coastal Commission on a qualifying lot.
Rear setback: 4 ft (detached); same as primary dwelling for attached; none for conversions of existing structures. Side setback: 4 ft; 6-ft wall-to-wall building separation required. Front setback: 15 ft for detached ADUs; attached ADUs follow the underlying zone. Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
1 space per ADU (may be tandem on driveway, unenclosed); waived within 1/2 mile of transit, in historic districts, for conversions, and other Gov. Code 66314 exemptions; no replacement parking for demolished garages. 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; required for JADUs with recorded covenant. 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 Torrance is typically 60 days from complete application per state law (SB 543 deemed-approval applies from 2026). Plan check: Plan review with a full corrections list returned within the 60-day statutory window; City of Torrance Design Guidelines apply (Torrance Tract Design Guidelines in the historic overlay). Pre-approved plans availability: Yes — City of Torrance Pre-Approved ADU Program through the Building & Safety Division.
Average ADU rental income in Torrance: 1-bedroom units rent for $2,100-$2,400/month, 2-bedroom units for $2,600-$3,100/month. Short-term rentals: No — ADUs and JADUs may not be rented for less than 30 days. Expected ROI: 5-8% annual return (gross rental yield estimate).
The minimum lot size for an ADU in Torrance is No minimum lot size. 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 Torrance, a garage conversion typically costs $70,000-$160,000. The key advantages are lower cost (no foundation work), potential setback exemptions, and faster permitting. Read our complete garage conversion guide.