ADU Builder in El Segundo, CA: Local Rules, Costs and Permits

How big can an ADU be on an El Segundo single-family lot?

On a single-family residential (R-1) lot in El Segundo, the city allows an attached ADU up to 49 percent of the primary dwelling unit, a detached ADU up to 1,200 square feet, and a junior accessory dwelling unit that must be attached and no larger than 500 square feet. The city also writes an exception into its code so a new ADU can exceed the maximum floor area ratio, the lot coverage limit, or the aggregate 1,200 square foot detached accessory structure limit by 850 square feet for a one-bedroom unit or 1,000 square feet for a two-bedroom unit.

How tall can an ADU be in El Segundo, and how far back does it have to sit?

El Segundo limits an ADU in the R-1 zone to 2 stories, 32 feet for a sloped roof and 26 feet for a flat roof. The front yard setback is a minimum of 22 feet from the front property line. A detached unit needs a 4 foot side yard setback and a 4 foot rear yard setback, while an attached unit takes 10 percent of the lot width on each side, not less than 3 feet and not more than 6 feet. Converting part of an existing structure to an ADU needs no setback at all.

How long does an El Segundo ADU permit take, and what do you submit?

The city takes building permits through its E-Z Permit Hub, where applicants register, upload plans, pay fees, follow reviews, request inspections and talk to staff in one place. For a new ADU the Planning Division wants a scope of work on the cover sheet, a fully dimensioned site plan, dimensioned floor plans, elevations, and where the project calls for them a site survey, a demolition plan and a landscaping and irrigation plan. Building and Safety asks for a minimum of three complete sets of plans plus one additional architectural set for the County Assessor, on sheets at least 18 by 24 inches. State law sets the backstop: written notice of completeness within 15 business days, a decision within 60 days, and a complete application the city does not act on in that time is deemed approved.

What does an ADU cost in El Segundo, and what fees does the city charge?

L Square publishes configured prefab prices: $180,000 for Model 600, $240,000 for Model 800A and Model 800B, $295,000 for Model 1000A and Model 1000B, and $354,000 for Model 1200. Those are unit prices, not a quote for your lot. On the city side, El Segundo charges a development impact fee when a new ADU is larger than 750 square feet, and it prices the rest of the permit through the ADU Fee Calculator on the E-Z Permit Hub, where you answer questions about the size of the proposed ADU and the main residence and get an estimate of plan check, permit and development impact fees. State law removes impact fees from an ADU of 750 square feet or less and from a JADU of 500 square feet or less, and it lets the city charge no utility connection fee or capacity charge for an ADU unless the unit was built with a new single-family dwelling.

Can I rent an ADU in El Segundo, and what should I check before I build?

An ADU cannot be used for short-term rental in El Segundo. The city home sharing permit covers renting for 30 consecutive days or less inside the primary residence while the owner lives on site, and it requires the owner to live in the unit 183 days a year, carry at least $1 million in liability insurance, and limit guests to two adults per bedroom. The city's ADU covenant works the other way and sets a floor of 30 days on any rental of the unit. Before you design, check whether your lot sits inside the special LAX noise contour area in the northwest part of the city, where extra sound insulation may apply, and see whether the city's pre-approved ADU plan program has a design you can use. The program is active, but no pre-approved plans are posted for property owners to choose from yet.

Official El Segundo ADU sources

• The city's ADU Application Handout sets the R-1 standards: an attached ADU up to 49 percent of the primary dwelling unit, a detached ADU of 1,200 square feet maximum, a JADU that must be attached and 500 square feet maximum, 2 stories with 32 feet for a sloped roof and 26 feet for a flat roof, a front yard setback of at least 22 feet, a detached side and rear yard setback of 4 feet, an attached side yard setback of 10 percent of the lot width, and a code exception that lets a new ADU exceed the lot coverage limit by 850 square feet for one bedroom. Official source
• The city's ADU and JADU resources page states that ADUs are permitted by right throughout any zone where residential uses are permitted, that ADU development standards are in El Segundo Municipal Code section 15-4E-3 and JADU general requirements and development standards are in section 15-4F-2, and that one junior accessory dwelling unit is permitted per lot zoned for single-family residences. The page also describes an ADU Permit Fee Calculator on the city's E-Z Permit Hub. Official source
• The city's Pre-Approved ADU Plan Program page states that the program is active but that no pre-approved ADU plans are available for property owners yet. Pre-approval review is limited to building safety, planning, police, fire and the mechanical, electrical and plumbing reviewers, so plan review fees are lower than a normal building permit review. Pre-approved plans expire at the end of the relevant state code cycle. The page also states that the northwest portion of the city falls within LAX noise contours where extra sound insulation requirements may apply. Official source
• The city's Plan Check Submittal Requirements page states that a minimum of three complete sets of plans and one additional architectural set for the County Assessor must be submitted for an accessory dwelling unit, with a site plan, dimensioned floor plans and elevations. Plans must be legible, fully dimensioned and drawn to scale, at a minimum of 1/8 inch scale with 1/4 inch recommended, on sheets that are 18 by 24 inches minimum with 24 by 36 inches recommended, and separate permits may be required for electrical, mechanical, plumbing, grading and demolition. Official source
• The city's Short-Term Home Sharing Rental Permit Program page states that an accessory dwelling unit may not be used for short-term rental, and defines home sharing as renting for 30 consecutive days or less of one or more bedrooms in the primary residence while the host lives on site. The program requires the owner to live in the dwelling unit 183 days a year, carry a minimum of $1 million in liability insurance, and limit occupancy to two adults per bedroom not including children under 13. Official source
• In a letter dated October 8, 2025, the California Department of Housing and Community Development told the City of El Segundo that the most recent ADU ordinance on file with the department is from 2017 and may be outdated and out of compliance with state ADU law. The letter states that if an existing ADU ordinance fails to meet state ADU law requirements, the ordinance is null and void and the local jurisdiction must apply the standards in state ADU law until it adopts a compliant ordinance, and it asks the city for a response by November 7, 2025. Official source
• California Government Code Section 66317 provides that a permitting agency must give written notice of whether an accessory dwelling unit application is complete no later than 15 business days after receiving it, must approve or deny a completed application within 60 days, treats a completed application the agency has not acted on in that time as approved, and tolls the 60-day period for the time an applicant requests a delay. It also provides that an ADU permit application is considered and approved ministerially without discretionary review or a hearing. Official source
• California Government Code Section 66314 provides that parking for an accessory dwelling unit shall not exceed one parking space per unit or per bedroom, whichever is less, and that a local agency shall not require replacement parking spaces for any garage, carport or parking structure converted into an accessory dwelling unit. It also provides that the total floor area of a detached accessory dwelling unit shall not exceed 1,200 square feet and that an attached accessory dwelling unit shall not exceed 50 percent of the existing primary dwelling. Official source
• California Government Code Section 66311.5 provides that a local agency, special district or water corporation shall not impose any impact fee on the development of an accessory dwelling unit that has 750 square feet of interior livable space or less, or a junior accessory dwelling unit with 500 square feet of interior livable space or less, and that any impact fee charged for a larger accessory dwelling unit is charged proportionately in relation to the square footage of the primary dwelling unit. Official source