ADU Builder in Carson, CA: City Rules, Fees and Permits

What are the ADU rules in Carson?

State law sets the floor and Carson adds a planning step in front of the building plan check. The city's ADU application instructions say an applicant must first obtain ADU approval from the Planning Division, and that this approval step screens the proposal against the state's ADU guidelines before Building Plan Check starts. The city asks for a completed ADU Plan Review application plus one set of electronic plans, and it issues the approval only after a covenant, described as a declaration of restrictions, is signed and notarized. The plan set has to carry a site plan, floor plan and building elevations, on sheets at least 11 by 17 inches and no larger than 24 by 36 inches, drawn at 1/4 inch to 1 foot or 1/8 inch to 1 foot. Government Code Section 66321 stops the city from setting a maximum below 850 square feet of interior livable space, or 1,000 square feet for a unit with more than one bedroom, and it requires the city to allow at least 800 square feet of interior livable space with four-foot side and rear yard setbacks. The same section allows a 16-foot detached unit and 18 feet within one-half of one mile of a major transit stop, while Section 66314 caps a detached unit at 1,200 square feet and an attached unit at 50 percent of the primary dwelling.

How long does an ADU permit take in Carson?

Two reviews sit between you and a Carson building permit. The city's ADU application instructions put the Planning Division ADU approval first, with eligibility screening against the state's ADU guidelines done before Building Plan Check, and applicants may apply for building permits only after the Planning Division notifies them that ADU approval has been issued. The Building and Safety Division says all plan check applications now have to be filled out and processed through the Carson Civic Access Portal, the city's new permitting system, and it offers SolarApp+ submittals, a building inspection, and a fire department inspection that the city lists as required. The planning counter publishes its hours as 7 AM to 6 PM Monday through Thursday at 701 E. Carson Street. State law is the clock underneath all of it. Government Code Section 66317 requires written notice within 15 business days on whether an application is complete, approval or denial of a complete application within 60 days, and if the city does neither inside that window, the application is deemed approved.

How much does an ADU permit cost in Carson?

Carson publishes a fee schedule inside its development application form, and the numbers are specific. The AB 2533 application and checklist for legalizing a unit that predates the current code asks for an application fee of $1,973.64, made up of a review fee of $1,925.10 and a permit issuance fee of $48.54, and says the fee is non-refundable once paid. The city's fee schedule lists Building Plan Check & Inspection at 125% of Los Angeles County Building & Safety fees, a Community Development Technology Surcharge of 1.25% of building permits and related building fees, and General Plan Maintenance of 8.8% of building permits and related building fees. It also lists an extra planning plan check at $180.00 per plan check and a pre-application review at $1,310.00 per application. Impact fees are a separate line, because Government Code Section 66311.5 bars any impact fee on an accessory dwelling unit of 750 square feet of interior livable space or less and on a junior accessory dwelling unit of 500 square feet or less, and requires impact fees on a larger unit to be charged in proportion to the square footage of the primary dwelling. The same section says an accessory dwelling unit is not a new residential use for utility connection or capacity charges unless it was built with a new single-family dwelling.

How much does an ADU cost in Carson?

Start with L Square's published prefab prices, then add the site work. The configured models are Model 600 at $180,000 for 600 square feet with 2 bed and 1 bath, Model 800A and Model 800B at $240,000 each for 800 square feet with 2 bed and 2 bath, Model 1000A and Model 1000B at $295,000 each for 1,000 square feet with 3 bed and 2 bath, and Model 1200 at $354,000 for 1,200 square feet with 3 bed and 2 bath. Those are configured model prices from the lscontractor.com cost guide, not a quote for your lot, and they do not cover sewer and water connections, electrical panel work, foundations on sloped ground, permit fees, or finish upgrades. L Square is a licensed California contractor, CSLB #1095476, and prices an actual project after a site visit. Call (949) 374-7980 to set one up.

What should I check before you build an ADU in Carson?

Several checks decide whether a Carson lot can carry a unit, and the city's own forms point to them. The ADU application instructions require the site plan to show every existing and proposed building, all front, side and rear setback dimensions, the distance between structures, driveways, garages and carports, fences and gates, and any mechanical equipment. The floor plan has to show a kitchen sink and cooking appliance with a counter of at least 16 by 24 inches, and the elevations have to carry the total building height from finished grade to the highest point of the structure. If the unit was built before 2020 and you are legalizing it, the AB 2533 checklist asks for a site plan, a floor plan, photos of all sides of the unit, proof that it was constructed before January 1, 2020, and a completed Substandard Housing Inspection Checklist. That inspection has to be done by a California licensed general contractor with a B license, a licensed architect, or a licensed engineer, and it checks emergency egress, where a bedroom window needs a clear opening of 20 inches wide by 24 inches high and a net opening of 5.7 square feet, along with smoke and carbon monoxide alarms, sanitation, natural light of at least 8 percent and ventilation of at least 4 percent of floor area.

Can I legalize an ADU that was built before 2020 in Carson?

If the unit already exists and predates the current rules, Carson has a path for it, and it starts with a screening questionnaire. The city's AB 2533 eligibility form asks whether you can show the unit was constructed before January 1, 2020, whether the application includes added area beyond what existed before that date, whether the unit is occupied or habitable, whether it has its own exterior access, and whether it has its own kitchen and bathroom. It also asks you to confirm the unit will not be offered or rented to any individual for less than 31 days, which keeps short-term rentals out of the program. The city accepts several kinds of proof for the construction date, including the County Assessor's initial date recognizing the unpermitted dwelling unit, escrow documents identifying the unit and the year of construction, prior official building, planning or code enforcement records, and real estate transfer disclosure forms, with other documents considered case by case. Before you file, Carson asks that the Planning Division covenant be obtained and recorded, and proof of recordation has to be submitted before the permit is finalized.

Official Carson ADU sources

• The city's ADU application instructions say an applicant must first obtain ADU approval from the Planning Division, that the approval process provides eligibility screening by verifying that an ADU proposal complies with the state's ADU guidelines prior to Building Plan Check, that the submittal needs a completed ADU Plan Review application and one set of electronic plans, that a covenant signed and notarized is required before approval is issued, and that plan sheets must be no less than 11 by 17 inches and no larger than 24 by 36 inches at scales of 1/4 inch to 1 foot or 1/8 inch to 1 foot. Official source
• The city's AB 2533 application and checklist asks for an application fee of $1,973.64, made up of a review fee of $1,925.10 and a permit issuance fee of $48.54, and says the fee is non-refundable. It requires proof that the unit was constructed before January 1, 2020, asks that the unit not be offered or rented to any individual for less than 31 days, and requires a Substandard Housing Inspection Checklist completed by a California licensed general contractor with a B license, a California licensed architect, or a California licensed engineer. Official source
• The city's Planning Division fee schedule lists Building Plan Check & Inspection at 125% of Los Angeles County Building & Safety fees, a Community Development Technology Surcharge of 1.25% of building permits and related building fees, General Plan Maintenance of 8.8% of building permits and related building fees, an Extra Planning Plan Check of $180.00 per plan check, and a Pre-Application Review of $1,310.00 per application. Official source
• The city's Building and Safety page says the city now has a new permitting system that requires all plan check applications to be filled and processed through the Carson Civic Access Portal, and it lists SolarApp+ submittals, a Building Inspection, a Fire Department Inspection that the page marks as required, and counter hours of 7 AM to 6 PM Monday to Thursday at 701 E. Carson Street. Official source
• The city's Planning Resource Documents and Application Forms page lists an Accessory Dwelling Unit (ADU) Application among the planning applications that the Planning Division accepts, next to the Development Application Form with Fees, and it publishes the Planning Division address as 701 E. Carson Street, Carson, CA 90745. Official source
• California Government Code Section 66314 provides that the total floor area for a detached accessory dwelling unit shall not exceed 1,200 square feet, that an attached accessory dwelling unit shall not exceed 50 percent of the existing primary dwelling, and that parking requirements shall not exceed one parking space per accessory dwelling unit or per bedroom, whichever is less. Official source
• California Government Code Section 66317 requires a permitting agency to give written notice of whether an accessory dwelling unit application is complete not later than 15 business days after receiving it, to approve or deny a completed application within 60 days, and provides that if the local agency has not approved or denied the completed application within 60 days, the application shall be deemed approved. Official source
• California Government Code Section 66321 provides that a local agency shall not establish a maximum accessory dwelling unit size less than eight hundred fifty square feet of interior livable space, or one thousand square feet for an accessory dwelling unit that provides more than one bedroom, must permit an accessory dwelling unit with at least 800 square feet of interior livable space and four-foot side and rear yard setbacks, and must allow a height of 16 feet for a detached accessory dwelling unit and 18 feet within one-half of one mile walking distance of a major transit stop. Official source
• California Government Code Section 66311.5 provides that a local agency, special district or water corporation shall not impose any impact fee upon the development of an accessory dwelling unit that has 750 square feet of interior livable space or less or a junior accessory dwelling unit that has 500 square feet or less, that any impact fees charged for a larger accessory dwelling unit shall be charged proportionately in relation to the square footage of the primary dwelling unit, and that an accessory dwelling unit shall not be considered a new residential use for utility connection fees. Official source
• California Government Code Section 66315 provides that no additional standards, other than those provided in Section 66314, shall be used or imposed, including an owner-occupant requirement, except that a local agency may require that the property may be used for rentals of terms 30 days or longer. Official source
• The Department of Housing and Community Development's state ADU fact sheet says a local agency may not require rear and side setbacks greater than four feet for new construction accessory dwelling units, may not establish a maximum size of less than 850 square feet, or 1000 square feet if the unit contains more than one bedroom, may not impose impact fees on accessory dwelling units of less than 750 square feet or on junior accessory dwelling units, and may not limit the number of bedrooms. Official source