ADU Constructionin Santa Fe Springs, CA
ADU construction in Santa Fe Springs follows Municipal Code 155.644, which the City rewrote in 2024 to match state law. Planning must approve a complete application ministerially within 60 days, a detached or attached unit tops out at 850 or 1,200 square feet, and state law can override a local limit. Confirm lot specifics with Planning.
Santa Fe Springs is known for its industry, but most of its homes are houses on their own lots. Of its 5,927 housing units, the Census Bureau's 2024 five-year estimates count 58.2 percent as single-family detached, and the City's R-1 zone asks for lots of at least 5,000 square feet. The tracts were mostly built in the 1950s, with 45.3 percent of all units dating to that decade. The city incorporated on May 15, 1957, and its ADU ordinance is far newer than its houses.
This page covers which rules govern an ADU here, how many units a lot can hold, size and height, garage conversions, fees, building on former oil land and how the review runs. The Municipal Code text we cite comes from the GoCodebook mirror, because the City's official code host would not open for our tools, so confirm each limit with Planning. Cost ranges and the phase list are on our ADU construction page.
Santa Fe Springs Planning and Building rules that apply to ADU construction
Where adu construction permits come from in Santa Fe Springs: City of Santa Fe Springs Community Development Department, Building & Safety Division.
- Municipal Code 155.644 (as amended by Ordinance 1134, adopted January 23, 2024 per the code's history note) requires the Director of Planning and Development to approve ADU applications ministerially and issue a permit within 60 days of a complete application, with the application deemed approved if the City neither approves nor denies in that time; a denial must list the defective items and how to fix them.
- The code allows one ADU plus one JADU within the walls of the home on a single-family lot (155.644(D)(2)(a)), and at most two detached ADUs on a multifamily lot with at least four-foot side and rear setbacks. HCD's October 8, 2025 letter describes state law as allowing one converted or attached ADU, one detached ADU and one JADU, so ask Planning which count applies to a given lot.
- Size limits in 155.644(D)(5): a detached or attached ADU with one bedroom or fewer may not exceed 850 square feet, one with more than one bedroom may not exceed 1,200 square feet, and the minimum is 150 square feet. Side and rear setbacks are four feet, and an ADU that encroaches into the front setback is limited to 800 square feet.
- Height limits in 155.644(D)(7): 16 feet for a detached ADU, 18 feet within one-half mile walking distance of a major transit stop or high-quality transit corridor (plus two feet to match the main roof pitch) or on a lot with a multistory multifamily building, and for an attached ADU 25 feet or the height of the main dwelling, whichever is lower. No ADU may exceed two stories.
- Parking in 155.644(D)(11) and (12) is capped at one space per ADU, no replacement parking is required when a garage, carport or covered parking is demolished or converted, and no parking is required within one-half mile walking distance of public transit, in a historic district, inside the existing home or an accessory structure, or when a car share vehicle is within one block.
- Design standards in 155.644(E): a separate exterior entrance, no exterior stairway on a front or street-facing side, and windows or glass doors facing an adjoining property within 15 feet of a property line must be clerestory with the glass at least 6 feet above the floor or use frosted or obscure glass. ADUs need fire sprinklers only if the main home needs them.
- Impact fees under 155.644(D)(16): none on an ADU under 750 square feet (school fees none at or under 500 square feet), and proportional to the main home's square footage for ADUs of 750 square feet or more. Attached or in-home ADUs need no new utility connection or connection fee unless built with a new single-family home.
- The January 11, 2024 special City Council agenda proposed Ordinance 1134 to align the City's ADU and JADU rules with state law after SB 897, AB 2221, AB 916 and AB 1033, and its staff report says earlier Ordinance 1084 (March 2017) had been partly invalidated by those laws. The City took part in SCAG's Regional Early Action Program for ADU implementation.
Which ADU rules apply in Santa Fe Springs: Ordinance 1134, state law and the 2025 HCD letter
Section 155.644 of the zoning code carries the City's ADU rules, and its history note shows Ordinance 1134, adopted January 23, 2024. The City Council's January 11, 2024 agenda said the update would align local rules with state law after SB 897, AB 2221, AB 916 and AB 1033, and that the earlier 2017 ordinance had been partly invalidated by those laws. The City also took part in SCAG's Regional Early Action Program for ADU implementation.
The state housing department sees it differently on paper. Its Letter of Technical Assistance dated October 8, 2025 says the most recent ADU ordinance on file with HCD is from 2017, that the ordinance may be out of compliance, and it asked for a response by November 7, 2025. Its records may simply not reflect the 2024 ordinance. We could not confirm what the City sent back.
Why it matters to you: where a local number and a state standard differ, the state standard can win. The City's ADU page links the ordinance and the application, so start there and ask Planning to confirm the figure for your lot.
How many units fit on a Santa Fe Springs lot: ADU, JADU or both?
On a single-family lot, Section 155.644(D)(2)(a) allows one ADU plus one junior ADU within the walls of the house. On a multifamily lot it allows at most two detached ADUs, with side and rear setbacks of at least four feet. HCD's October 2025 letter reads state law more broadly: one converted or attached ADU, one detached ADU and one JADU. We could not reconcile the two readings, so ask Planning which count applies to a given lot before you pay for drawings.
A junior ADU is capped by state law at 500 square feet, sits inside the single-family house and needs an efficiency kitchen and a separate entry. The ADU versus JADU guide compares the two in detail. State law does not allow a city to require the owner to live on site for an ADU, and we did not find an owner-occupancy rule in the adopted City text we read.
How big and how tall can an ADU be in Santa Fe Springs?
Under 155.644(D)(5), a detached or attached ADU with one bedroom or fewer may not exceed 850 square feet, one with more than one bedroom may not exceed 1,200, and the minimum is 150. Side and rear setbacks are four feet. An ADU that encroaches into the front setback is limited to 800 square feet.
Height limits under (D)(7) are 16 feet for a detached unit, 18 feet within one-half mile walking distance of a major transit stop or high-quality transit corridor, and 25 feet or the height of the main dwelling, whichever is lower, for an attached unit. No ADU may exceed two stories.
The design standards in 155.644(E) ask for a separate exterior entrance and bar an exterior stairway on a front or street-facing side. A window or glass door facing a neighbor within 15 feet of the property line must be clerestory with the glass at least 6 feet above the floor, or use frosted or obscure glass. That rule shapes the floor plan more than most owners expect.
Converting a 1950s garage into an ADU in Santa Fe Springs, and legalizing an old one
Parking rules are generous. Section 155.644(D)(11) and (12) caps parking at one space per ADU, requires no replacement parking when a garage, carport or covered space is demolished or converted, and requires none within one-half mile walking distance of public transit, in a historic district, inside the existing home or an accessory structure, or when a car share vehicle is within one block. ADUs need fire sprinklers only if the main house needs them.
A garage conversion often means an infilled door opening, a new floor build-up, a bathroom and its own electrical and plumbing plan. Our garage conversion permit guide walks through that sequence, although it describes Los Angeles City rules and not Santa Fe Springs.
Under 155.644(G), a unit built without a permit before January 1, 2018 cannot be denied for building standard or zoning violations unless correction is needed to protect health and safety, and the City must delay non-safety enforcement for five years on request. State law may reach units from later years, so ask Planning about the date for your unit.
ADU fees and utility connections in Santa Fe Springs: what the 750 square foot line covers
Under 155.644(D)(16), the City charges no impact fee on an ADU under 750 square feet, with school fees at none for units of 500 square feet or less. For ADUs of 750 square feet or more, impact fees must be proportional to the main home's square footage. Attached or in-home ADUs need no new utility connection or connection fee unless they are built with a new single-family home.
A detached unit is a different matter, and state law keeps utility connection and capacity charges separate from the impact fee exemption. We found no City ADU fee schedule, and the FY 2026 to 2027 Building and Safety schedule lists a $46.27 permit issuance fee, a 2 percent plan maintenance fee and plan check at 85 percent of the building permit fee under Section 150.001.004. Building permit fees come from a valuation table we could not extract, so the sewer, water and electric lines belong in a written proposal as separate items.
A Construction Waste Management Plan form goes in with every building permit application, with a goal of recycling at least 75 percent of project waste under Title V, Chapter 50.
Building an ADU slab on former oil land: wells, soil and the engineer's stamp
Few ADU pages have to ask this question. The City's Safety Element draft says plugged, abandoned and active oil wells and contaminated soils complicate reuse of former oil field land, and that oil operations are down to about 10 city blocks. We found no source on wells under the 1950s single-family lots, so ask Planning and the firm what records exist for your parcel before the slab is poured.
The same draft says the soils are sand, loam and clay, with liquefaction hazard areas in the north, west of Norwalk Boulevard and south of Imperial Highway, but that liquefaction is unlikely because the water table is deeper than 50 feet. The city lies close to the 1987 Whittier Narrows earthquake epicenter, and the City's amended R301.1.3.2 requires an architect or engineer stamp on many wood-frame dwelling plans. Whether it reaches a one-story ADU depends on the design and seismic category, so we do not assume either way. Design wind speed is 95 mph, Exposure C.
From application to final: how an ADU job runs in Santa Fe Springs
Section 155.644 requires the Director of Planning and Development to approve ADU applications ministerially and issue a permit within 60 days of a complete application, with the application deemed approved if the City neither approves nor denies in that time. A denial must list the defective items and how to fix them. State law, in changes that took effect January 1, 2026, also asks the agency to say within 15 business days whether the application is complete. Plans go in through the GoPOST portal, and the permit counter is open Monday through Thursday only.
The City keeps a Local ADU Designers List of designers with recently approved plans in Santa Fe Springs, and designers who want pre-approved plans submit them through GoPOST. Inspections are requested 24 hours ahead. As MDG Builders, CSLB #1040337, we manage the design, permits and schedule as general contractor, and licensed subcontractors pour the slab and run the utilities. The subcontractor guide explains that handoff.
ADU photos from Santa Fe Springs and nearby homes
ADU scenes tied to Santa Fe Springs and the towns around it, from garage conversions and slabs to finished studios. Tap a photo to enlarge it.
What adu construction costs around Santa Fe Springs
The ADU construction page prices a studio or one-bedroom garage conversion at about $100,000 to $200,000 and a new detached unit of 400 to 800 square feet at about $200,000 to $400,000. Three independent sources shape those ranges: a UC Berkeley survey of Los Angeles County projects from 2018 and 2019, with a median of $100,000, garage units at $90,000 and detached units at $180,000; a 2020 Terner Center estimate of $148,000 for Los Angeles; and Remodeling magazine's 2025 Cost vs. Value job cost of $178,536, with 39.9 percent recouped at resale. None is a Santa Fe Springs quote. Directory pages that price the city's ADUs state no method, so we did not use them. The ADU cost guide and the room addition versus ADU guide help you choose a route. Nearby cities apply the same state law in their own way, so compare ADU construction in Norwalk, Whittier, La Mirada, Downey and Los Angeles. A bath inside the unit is on our Santa Fe Springs bathroom page, an attached home addition on the Santa Fe Springs room addition page, and the Santa Fe Springs area page lists every trade we cover in the city.
| 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 Santa Fe Springs
Santa Fe Springs ADU questions, answered
Can I build an ADU in Santa Fe Springs?
Yes, on most lots with an existing home. Municipal Code 155.644 allows one ADU plus one junior ADU on a single-family lot, and Planning must approve a complete application ministerially within 60 days. HCD's 2025 letter suggests state law may allow more, so ask Planning which count applies to your lot.
How big can an ADU be in Santa Fe Springs?
A detached or attached unit with one bedroom or fewer may reach 850 square feet, and one with more than one bedroom 1,200 square feet. The minimum is 150, side and rear setbacks are four feet, and a unit that reaches into the front setback is capped at 800. Height tops out at 16 feet for a detached unit.
How much does it cost to build an ADU in California?
Plan on about $100,000 to $200,000 to convert a garage and about $200,000 to $400,000 to build a detached unit of 400 to 800 square feet. Those bands combine a Berkeley survey, a Terner Center estimate and Remodeling magazine's 2025 report, and none is a Santa Fe Springs quote. Only your written proposal sets a price.
Do I need to provide parking for my ADU?
Usually not. The City caps parking at one space per ADU and requires no replacement parking when a garage or carport is converted or demolished. No space is required within one-half mile walking distance of public transit, inside the existing home or an accessory structure, or when a car share vehicle is within one block.
What is the difference between an ADU and a JADU?
A JADU is a smaller unit, up to 500 square feet, built inside the walls of a single-family house with an efficiency kitchen and a separate entry. An ADU can be detached, attached or converted from a garage and is larger. Santa Fe Springs allows one of each on a single-family lot, per its code.
Can I rent out my ADU or sell it separately?
You can rent it, but a city may require terms of 30 days or longer. State law does not let you sell an ADU separately from the house, except to a qualified low-income buyer through a nonprofit or under a city condominium ordinance. We did not find a Santa Fe Springs ordinance of that kind.
How long does it take to get an ADU permit?
The City must act within 60 days of a complete application, and the application is deemed approved if it does not. State law adds a 15 business day completeness notice. Directory pages quoting longer waits give no source. Design, drawings and corrections add weeks before the clock starts.
Do I need a permit to convert my garage into an ADU?
Yes. A conversion is building work that adds a bathroom, a kitchen and new electrical and plumbing, and it goes through the same ministerial review. State law does not require replacement parking for the lost garage. Ask Planning whether your lot has a record of the old garage permit.
Tell us about your Santa Fe Springs ADU plans
Let us know the neighborhood, whether you are weighing the garage or the backyard, and when the house was built, and the first visit will start from the City's 60 day review.