Accessory Structures in Downey, CA: What Residents Actually Need to Know

If you live in Downey or are thinking about moving there, accessory structures are one of those things you probably won't think about until they affect you directly. Downey has 5 specific rules on the books covering different aspects of accessory structures, and some of them might surprise you.

Shed Rules

Downey Municipal Code Article IX regulates accessory structures. Detached accessory structures and attached patio covers may occupy up to 50% of the required rear yard. Structures must comply with setback, height, and lot coverage requirements.

Key details: Code Section: Art. IX, Ch. 4. Rear Yard Coverage: 50% max for accessory structures. Max Height: One story. Small Structures: Under 120 sq ft may be permit-exempt. Building & Safety: (562) 904-7142.

Unpermitted structures are subject to code enforcement. Violations may result in demolition orders, fines, and requirements to obtain retroactive permits.

Garage Conversions

Downey allows garage conversions to ADUs under state law and DMC §9414.08. Replacement parking is not required. No minimum setback for conversions. Height limits don't apply to conversions. Driveway max 20 feet wide.

Key details: Replacement Parking: Not required. Setback: None for conversions. Driveway Max: 20 ft wide. Code Section: DMC §9414.08; GC §65852.2.

Unpermitted conversions face code enforcement. A building permit is required for all garage conversions. Contact Community Development at (562) 904-7154.

Tiny Homes

Tiny homes on foundations in Downey are regulated as ADUs under CA Gov Code 65852.2. Tiny homes on wheels are treated as RVs and cannot be used as permanent dwellings. ADU rules allow up to 1,200 sq ft detached.

Key details: On Foundation: Regulated as ADU. On Wheels: Treated as RV, not dwelling. Max Size: 1,200 sq ft detached ADU. State Law: CA Gov Code 65852.2.

Unpermitted dwellings: removal or retroactive permitting. Zoning violations: fines and required relocation. Occupancy without certificate: prohibited.

ADU Rules

Downey regulates ADUs under DMC §9414.08. Detached ADUs up to 1,200 sq ft allowed. Max 2 bedrooms. Height: 16 ft detached, 25 ft attached. 4-foot setbacks. Pre-approved ADU plans available through the city.

Key details: Max Size: 1,200 sq ft (detached). Max Bedrooms: 2. Height (Detached): 16 ft. Code Section: DMC §9414.08.

Unpermitted ADUs face code enforcement. Short-term rental of ADUs may be prohibited. Contact Community Development at (562) 904-7154.

Carport Rules

Carports in Downey require a building permit. They must comply with zoning setback requirements and cannot encroach into required yards without approval. Height limited per zone standards.

Key details: Permit: Required. Setbacks: Per zone requirements. Height: Per zone maximum. Materials: Must meet building code.

Unpermitted carports: stop-work orders, required removal or retroactive permitting with penalty fees. Fines $200 to $1,000.

The Bottom Line

Downey's accessory structures rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming Downey is broadly strict or permissive.

This guide is based on Downey's current municipal code. Local rules can and do change, so check the individual ordinance pages for the latest details, penalties, and FAQs.