ADU Constructionin Redondo Beach, CA
ADU construction in Redondo Beach is a ministerial building permit job, approved without a hearing, but near the water it can also need a Coastal Development Permit decision from the City. The state housing department found the City's 2023 ordinance non-compliant, so where City rules conflict with state law, ask Planning and expect state law to control.
Redondo Beach has been adding housing since it was a railroad and steamship resort in the 1890s, and its population reached 54,772 by 1965 as South Bay tracts filled in. Only 4.0 percent of today's units date from the 2010s and 0.6 percent from 2020 on, so most lots hold a house, a garage and a yard planned decades before accessory dwellings were allowed.
This page covers how to build an ADU under City code and state law, the Coastal Zone paths, size and height, garage conversions, historic lots, plan check and what moves the budget. Regional price ranges are on our ADU construction page, and the Redondo Beach overview lists the rest of our work here.
What the Redondo Beach Planning Division and Building and Safety say about ADUs
Where adu construction permits come from in Redondo Beach: City of Redondo Beach Community Development Department, Building and Safety Division.
- Accessory dwelling units and junior ADUs are permitted uses on lots with a single-family or multi-family dwelling, require a building permit, and are approved ministerially without discretionary review or a hearing; the Community Development Director and Chief Building Official must approve or deny all permits within 60 days of a complete, code-compliant application (RBMC 10-2.1506(a)). The City's ADU page repeats the 60-day ministerial process and says the current ordinance is No. 3264-23.
- Streamlined ADUs in the City's code are: an ADU or JADU wholly within the existing or proposed space of a single-family home or existing accessory structure (a JADU is capped at 500 square feet and needs exterior access), and a new detached ADU of up to 800 square feet at least 4 feet from side and rear lot lines, up to 16 feet tall (18 feet within half a mile of major transit, plus 2 feet to match the main roof pitch). A 5-foot separation applies between a dwelling and an accessory structure unless fire rating is met (RBMC 10-2.1506(b)).
- ADUs that do not meet the streamlined tests (such as a conversion of an accessory structure or an attached unit needing more than a 150 square foot addition) are limited to one per lot, with a living area of up to 850 square feet for a studio or one bedroom and 1,000 square feet for more than one bedroom (at least 150 square feet), and an attached unit of no more than two stories may be 25 feet tall or the primary dwelling's height limit, whichever is lower. A 4-foot side and rear setback applies except for units in existing living area or existing accessory structures and same-location, same-size replacements (RBMC 10-2.1506(c)).
- For non-streamlined ADUs the only design standards are similar siding, colors, window types, trims, roofing materials and roof pitch to the main home, entrances for attached ADUs on the side and rear and not visible from the street where feasible, a detached ADU entrance at least 4 feet from any lot line, alley driveway access where the lot abuts an alley, and application of the Preservation Ordinance, including any Mills Act contract (RBMC 10-2.1506(c)(4)(e)).
- One off-street parking space is required for a non-streamlined ADU unless it is within half a mile walking distance of public transit (the code lists further exceptions that were not read in full), and an ADU permitted after January 1, 2025 in a single-family zone must have the owner living in either the primary unit or the ADU (RBMC 10-2.1506(a)(10) and (c)(8)). The City's ADU page also says the owner-occupancy rule applies to either the primary dwelling or the ADU in single-family zones and bars short-term rentals under 30 days.
- An ADU addition, or a second unit added to a lot that already has a single-family home, goes through Administrative Design Review by the Community Development Director (RBMC 10-2.2500(a)(7)), and the Objective Residential Standards apply and prevail over the general design criteria. The City's ADU page lists an AB 1332 pre-approved plans page and an AB 2234 checklist page on the Building and Safety site, which were not opened.
- In the Coastal Zone, an ADU or JADU contained entirely within existing living area of a single-family home, without removing or replacing roofs, exterior walls or foundations, is exempt from a Coastal Development Permit; other ADUs are not exempt but may qualify for a CDP hearing waiver if they comply with RBMC 10-5.1506 and have no coastal impact, and the setbacks in the LCP apply where needed to protect coastal resources (RBMC 10-5.2208, 10-5.2217 and 10-5.1506).
- The City's ADU page says Coastal Act policies for habitats, public access and coastal hazards still apply in the Coastal Zone, that setbacks or design rules protecting wetlands or ESHA, public view corridors or flood hazards cannot be waived, and that the City may use Categorical Exclusion Orders to exempt eligible infill ADUs from standard CDPs when coastal resources are not at risk.
How do you build an ADU in Redondo Beach: City code or state law?
Both, and when they disagree the state wins. The City's ADU page lists Ordinance 3264-23 as current and RBMC 10-2.1506 as the code section, which treats ADUs and junior ADUs on lots with a house or an apartment building as ministerial building permits with no hearing. The Community Development Director and the Chief Building Official must approve or deny within 60 days of a complete application.
The state housing department reviewed an earlier City ordinance, number 3210-20, in a May 12, 2023 letter and found it did not comply with state ADU law in several respects: the definition of a junior ADU, the 60-day approval duty, a rule limiting rentals to one unit and a cap on streamlined units. We did not read Ordinance 3264-23 or any later letter, so we cannot say whether it fixed each finding. Ask Planning which provision applies to your lot, and treat state law as the floor.
Since January 1, 2026, state law also gives a city 15 business days to say whether an application is complete and then 60 days to act, and an application left unanswered is deemed approved under Government Code 66317. The City's ADU page is the place to start.
How big, how tall and how close to the line can a Redondo Beach ADU be?
The code's streamlined units are an ADU or junior ADU inside the existing or proposed space of a house or an existing accessory structure, and a new detached ADU of up to 800 square feet that sits at least 4 feet from side and rear lot lines and rises no more than 16 feet, or 18 feet within half a mile of major transit. A junior ADU is capped at 500 square feet and needs its own exterior entry. A 5-foot separation from other structures applies unless fire rating is met.
Units that miss those tests are limited to one per lot, up to 850 square feet for a studio or one bedroom and 1,000 square feet for more bedrooms, and an attached unit of no more than two stories may reach 25 feet or the house's height limit, whichever is lower. State law sets floors under these numbers: a city may not cap a unit below 850 square feet, and a detached unit can reach 1,200. Ask Planning which number your lot is held to.
Appearance rules are short. A non-streamlined unit uses siding, colors, window types, trim, roofing and roof pitch similar to the main house, and an attached unit's entrance goes on the side or rear and out of street view where feasible.
Garage conversion to an ADU in Redondo Beach: the two-car garage rule and state law
Redondo Beach requires a single-family home to keep two parking spaces in a private enclosed garage, each at least 9 by 19 feet, with entrances and overhead obstructions at least 88 inches clear, under RBMC 10-2.1704 and 9-1.11. A garage conversion removes that garage, so on its face it collides with the rule.
State law answers the collision for ADUs. Government Code 66314 and 66322 bar a city from requiring replacement parking when a garage, carport or covered space is converted or demolished for an ADU, and a conversion inside an existing accessory structure is one of the four state-protected types, which may add up to 150 square feet for access. The City's ADU section lists its own parking exceptions, and we read only the first, half a mile walking distance of public transit. Confirm the path with Planning before drawing.
A converted garage still has to work as a home, with its own entrance, sanitation and cooking space, and Building and Safety's plan check will tell you what else. If the plan needs a new foundation, roof or exterior wall, say so early, because the coastal exemption for interior ADUs does not cover replacing them.
ADU in the Redondo Beach Coastal Zone: exempt, waived hearing or a full permit?
The City, not the Coastal Commission, issues Coastal Development Permits here. The Commission certified the Land Use Plan in 1981, the inland Area One program in 2003 and the Harbor-Pier Area Two in 2010, when voters approved Measure G. In our sample of 178 points set against a state copy of the 1977 boundary, 29 points, about 16 percent, fell in the Coastal Zone along the western shoreline. Treat that as a sample and check the City's boundary map for your address.
Three outcomes follow. An ADU or junior ADU entirely inside the existing living space of a single-family home, with no replacement of roofs, exterior walls or foundations, is exempt. Another ADU is not exempt, but the City may waive the public hearing if it meets RBMC 10-5.1506, has no coastal impact and draws no written hearing request within 15 working days of notice. Anything else needs a full permit, and state law asks for action on a coastal permit within 60 days, alongside the ADU.
Coastal Act policies still apply. The City says setbacks or design rules that protect wetlands, public view corridors or flood hazards cannot be waived, and it may use Categorical Exclusion Orders for eligible infill ADUs. A claimed exemption needs the Director's written determination before work starts.
ADU behind an Original Townsite house: what the Preservation Ordinance adds
South Redondo's Original Townsite, a National Register district since June 30, 1988, holds many of the City's local landmarks, mostly houses and small apartment buildings from the 1890s to the 1930s on streets such as Gertruda Avenue, Garnet Street and Avenue C. The Preservation Ordinance, RBMC Title 10 Chapter 4, applies to ADUs on historic lots, and any Mills Act contract on the property is part of the review.
On a landmark or district property, exterior work visible from a public right of way needs a Certificate of Appropriateness even when no other permit is required, and the ordinance counts paint color as an alteration. A property listed as a potential historic resource needs the certificate only to demolish, remove or relocate exterior features. Ask Planning which status your parcel has before an architect sizes the unit.
An ADU addition, or a second unit added to a lot that already has a house, also goes through Administrative Design Review under the Objective Residential Standards adopted in 2023, which prevail over the general criteria. That review happens at Planning first, and the plans need Planning's stamp before Building and Safety will accept them.
Plans, plan check and permit expiry for a Redondo Beach ADU
Everything is filed electronically in the City's iWorQ portal. The plan set goes in as PC1_PLANS, with structural calculations and registered energy calculations as separate files where they apply, and Planning stamps 'Reviewed for Submittal/Ok to Submit' before Building and Safety takes it. The City lists a first building review of up to three to four weeks and a second of two to three, counting Building only, not Planning, Engineering or Fire.
Inspections are requested by 3 p.m. for next-day service, and a final inspection on a single-family lot serves as the certificate of occupancy. Sprinklers need a question to the plan checker: Redondo Beach's residential code requires them in one- and two-family dwellings, while state law says an ADU cannot trigger sprinklers in the main house and needs none if the main house needs none.
Permits lapse. RBMC 9-1.06 makes a permit invalid if work does not start within 12 months, with 180-day extensions up to two years in all, while the residential chapter's RBMC 9-22.05.4 still says 180 days to start and two years to finish. The two sections conflict, so ask Building and Safety which one is printed on your permit, and ask for any extension in writing.
Owner occupancy, rentals and fees: what moves a Redondo Beach ADU budget
The City's ADU page says an ADU permitted after January 1, 2025 in a single-family zone needs the owner living in the main house or the ADU, and it bars rentals under 30 days. State law, Government Code 66315, does not allow an owner-occupancy requirement for ADUs and lets a city require only rentals of 30 days or longer. The two statements disagree, so ask Planning, and remember that state law controls.
Fees come in layers. State law bars impact fees on an ADU of 750 square feet or less and keeps utility connection charges separate. The county charges sewer connection fees when demand increases, a Dig Alert number is needed before an excavation permit is valid, and Cal-OSHA rules apply to vertical cuts over 5 feet. The City's fee schedule sits on a Finance page we did not open, so no City dollar amounts appear here.
Site work often decides the budget: trenches for sewer and water, a panel upgrade and equipment access. With a median owner-occupied value of $1,279,200 and a median gross rent of $2,691 in the 2024 survey, owners weigh those costs against rent, and we do not forecast rents.
ADU details from Redondo Beach area lots
Framing, conversions and finishes from ADU projects near Redondo Beach. Tap a photo to enlarge it.
What adu construction costs around Redondo Beach
Our ADU construction page lists regional figures of roughly $100,000 to $200,000 for turning a garage into a unit and $200,000 to $400,000 for a new detached ADU of 400 to 800 square feet, resting on a University of California survey of 2018 and 2019 projects, Remodeling magazine's 2025 Cost vs. Value figure of $178,536 for a Los Angeles ADU and builder quotes, at medium-low confidence. One plan company's Redondo Beach page lists estimated builds of $215,000 to $350,000 for three designs and leaves out City fees, coastal permit fees and site work, which makes it a marketing range. See the ADU cost guide and the ADU vs JADU guide. A unit needs a bath, as in bathroom remodeling in Redondo Beach, and a larger house change may suit a room addition in Redondo Beach. Neighbors write their own rules: see Torrance, Los Angeles, Long Beach and the Redondo Beach overview.
| What it covers | Typical range |
|---|---|
| Garage conversion to a studio or one bedroom | $100,000 to $200,000 |
| New detached ADU, 400 to 800 sq ft | $200,000 to $400,000 |
| UC Berkeley survey, Los Angeles County median, 2018 and 2019 projects | $100,000 overall. $90,000 garage. $180,000 detached. |
| Terner Center and Berkeley CCI, 2020 | $148,000 Los Angeles estimate. $167,000 statewide average. |
| Remodeling Cost vs. Value 2025, Los Angeles | $178,536 job cost |
| Electrical and plumbing, Angi Los Angeles, January 2026 | Electrical $2,600 to $7,800. plumbing $3,900 to $10,400. |
| City permit and plan check fees | Not priced here |
Other work we manage in Redondo Beach
Redondo Beach ADU size, parking, coastal permit and rental questions
How do I build an ADU in Redondo Beach, and do I need a permit?
Yes, a building permit, filed in the City's iWorQ portal, and Planning stamps the plans first. The City treats ADUs as ministerial, with no hearing, and must act within 60 days of a complete application. In the Coastal Zone a coastal decision may come with it. Ask Planning which ordinance provision applies, because state law controls where the City's text conflicts.
What is maximum ADU size, and what does Redondo Beach allow?
A new detached ADU of up to 800 square feet is a streamlined unit, 4 feet from side and rear lines and up to 16 feet tall. Other units may reach 850 square feet for a studio or one bedroom and 1,000 square feet for more, and state law lets a detached unit go to 1,200. A junior ADU is capped at 500 square feet.
Can I convert a garage to an ADU, and do I replace the parking?
Yes, a garage can be converted, and state law bars a city from requiring replacement parking when it is converted for an ADU. The City's own code requires two enclosed garage spaces for a single-family home, so confirm the path with Planning before drawing. A conversion can add up to 150 square feet only for access.
Does an ADU in the Redondo Beach Coastal Zone need a Coastal Development Permit?
Not if it sits entirely inside existing living space of a single-family home without replacing roofs, exterior walls or foundations. Other ADUs are not exempt, but the City may waive the hearing if no one asks for one within 15 working days. The Director's determination comes before work starts, and the Coastal Act's resource protections still apply.
Do I have to live on the property to build or rent an ADU?
The City's page says owner occupancy applies to ADUs permitted after January 1, 2025 in single-family zones, but state law does not allow it for ADUs. A junior ADU is different, since state law ties owner occupancy to shared sanitation. Rentals of 30 days or longer are permitted, and shorter stays are barred. Ask Planning, and rely on state law.
How long does it take to get an ADU permit?
The City must approve or deny within 60 days of a complete application, and state law adds 15 business days to find it complete. Building review is listed at up to three to four weeks first and two to three weeks on the second round, and a coastal permit or Design Review can add time. Ask for a written phase schedule.
How much does it cost to build an ADU?
Regional ranges run about $100,000 to $200,000 for a garage conversion and $200,000 to $400,000 for a new detached unit of 400 to 800 square feet. They come from a University of California survey, Remodeling magazine's 2025 report and builder quotes. We found no Redondo Beach survey with a stated method, so site work and City fees stay on separate lines.
Can I build two units on one Redondo Beach lot, or a second home instead of an ADU?
In the R-1 and R-1A zones a two-unit project is a separate path from an ADU, approved ministerially under RBMC 10-2.505. Only individual owners, not corporations, may apply, the lot must be legally subdivided, and a deed restriction and easements must be recorded. It excludes lots on wetlands and certain fault, fire and flood areas.
Tell us about your Redondo Beach lot
Send the neighborhood, the lot size, the year the house was built, whether the garage still holds cars and how close you are to the water, and we will plan the visit from that.