ADU Constructionin Bellflower, CA
ADU construction in Bellflower follows Municipal Code Chapter 17.17, which caps an ADU at 1,200 square feet, bars rentals under 30 days and requires a recorded covenant. The chapter does not restate setbacks or height, so ask Planning, and state law controls where the City is silent. A new unit also needs a soils report.
Bellflower's backyards were farm lots before they were tracts. Emil Firth subdivided one-acre lots in 1904, and from 1906 Frank Woodruff's syndicate sold one-acre farms and town lots only 25 by 131 feet. The City's history says the narrow, deep lots of the north became apartment sites after the war, while the Housing Element says large tract homes filled the south in the 1950s. The result, per the Census Bureau's 2024 five-year tables, is 47.7 percent detached houses, 32.0 percent of units in buildings of five or more and 4.9 percent mobile homes, on parcels where about 88 percent are under half an acre.
That is why an ADU here is a question of fitting a unit onto a small lot and a liquefaction-susceptible slab. This page works through what the City's chapter says, what it leaves out, and what to ask Planning in writing. MDG Builders (CSLB #1040337) drafts the plans, files them and supervises the build as general contractor. The cost table and phase timeline are on our ADU construction page, and the Bellflower overview lists our other trades here.
What Bellflower's ADU chapter, City handouts and state law say
Where adu construction permits come from in Bellflower: City of Bellflower Planning Department, Building & Safety Division.
- ADU rules live in BMC Chapter 17.17 (Ordinances 1443, 1444 and 1446, adopted April and May 2025). The chapter is short: a final certificate of occupancy for an ADU or JADU cannot issue before the primary dwelling's, the owner must record a covenant approved by the City Attorney, rentals must be 30 days or longer, and an ADU, attached or detached, may not exceed 1,200 square feet of gross area (17.17.050). The chapter does not restate setbacks or height, and the City's Planning FAQ points to it for ADU development standards, so writers should say specifics are confirmed with Planning.
- JADU conditions in BMC 17.17.020: a JADU may not be sold separately, has size and attribute limits set by the Code, requires the owner to live in the home containing the JADU or in the JADU, and cannot be rented for less than 30 days.
- An ADU or JADU with a separate entrance or a new separate utility connection must apply for an address number from the Director (BMC 17.17.030), and each ADU must install its own utility connection subject to a connection fee or capacity charge unless State law says otherwise; ADUs pay development impact fees proportional to the primary dwelling's square footage (17.17.040).
- ADU submittal (Handout 13): email ptechnician@bellflower.ca.gov for requirements; the package needs the Building Permit application, full plans, structural calculations and energy reports in PDF, and a Title 24 energy package is always required. The document list names a vicinity map, site plan, existing and proposed floor plans, foundation and framing plans, details, plumbing, mechanical and electrical plans, and says a new detached structure may also require grading plans and review. The handout lists four plan sets even though it says submittals are electronic.
- Other agency approvals for ADUs (Handout 13): all ADUs are subject to a Fire Flow 195 form unless the Fire Plan Review approves otherwise; development fees apply to ADUs over 750 square feet; school development fees apply to all projects over 500 square feet; and AQMD notification is required for any wall removal or demolition over 100 square feet.
- A soils report with liquefaction study is required for additions of 750 square feet or more, new dwelling units and second-story additions (Handout 13), and BMC 15.60.040 (R401.4.1.1.5.1) requires a soils investigation report for all projects over 750 square feet or more than one story.
- The City's ADU Application (revised 07/26) asks for the project address and APN, whether the lot is in a parking district, whether the unit is new attached or detached construction, a garage conversion, a conversion of another structure or a JADU, the hardscape, building footprint and landscape areas, replacement and additional parking, and any easements (with proof if the easement holder will release it). Properties owned by an LLC or corporation must attach a Secretary of State Statement of Information or the application is incomplete.
- The ADU Application lists the reasons no parking may be provided: within a half mile walk of public transit, in an architecturally and historically significant district, the ADU is within the primary dwelling or an accessory structure, permit parking is required but not offered to the ADU occupant, within a block of a car-share vehicle, and no replacement parking is required when a garage or carport is demolished or converted.
What do Bellflower's ADU rules actually say?
Chapter 17.17 of the Municipal Code, adopted by Ordinances 1443, 1444 and 1446 in April and May 2025, is short. It says an ADU's final certificate of occupancy cannot issue before the main house's, the owner must record a covenant approved by the City Attorney, rentals must run 30 days or longer, and an ADU, attached or detached, may not exceed 1,200 square feet of gross area. It also covers address numbers, utility connections and impact fees.
What it does not do is restate setbacks, height or parking. The Planning FAQ points back to the Municipal Code for ADU standards, and we found no objective ADU standards document on the City site. We will not print a Bellflower setback or height number we cannot source. Ask Planning in writing which setback and height apply in your zone before drawings start.
State law fills the gap. HCD's ADU Handbook summarizes what a city must allow, including a new detached ADU of at least 800 square feet with side and rear setbacks of no more than 4 feet, and a local ordinance governs only where it is consistent with that law.
The City's own ADU application and handout are the documents the permit technicians work from, so ask for the current versions.
Can you build under SB 9 in Bellflower, or only a regular ADU?
The City posts an SB9 Application, revised 09/26, with boxes for one new unit, two new units and a lot split, and a no-parking checkbox for parcels within a half mile walk of a high-quality transit corridor or major transit stop, or within a block of a car-share vehicle. We could not find a local SB 9 chapter in the Title 16 or Title 17 chapter lists, so the form has no local ordinance behind it. State law controls, and Planning is the place to confirm how it will treat your lot.
The zone matters. The single-family zone sets a 7,000 square foot minimum lot, R-1 allows one unit per 5,000 square feet, and a lot of record under 8,000 square feet in the A-E Agricultural Estate zone follows R-1 standards but does not qualify for a newly built ADU. The City also lists a Housing Opportunity Overlay Zone, and a parcel's zone shows on the City GIS page.
Compare the routes before choosing. Our post on room addition or ADU weighs them, and the one on ADU versus JADU separates the unit types.
Does a new ADU in Bellflower need a soils report?
Yes for a new unit. The City's ADU handout requires a soils report with a liquefaction study for additions of 750 square feet or more, new dwelling units and second-story additions, and section 15.60.040 of the Municipal Code requires one for any project over 750 square feet or more than one story. A new detached ADU is a new dwelling unit, so budget for a geotechnical report and an engineered foundation before pricing the slab.
The reason is the ground. The 2017 Safety Element says all of Bellflower is susceptible to liquefaction, with historically highest groundwater from about 8 to over 30 feet down, shallowest in the south. The soil is alluvial fan and floodplain deposits of the San Gabriel River, whose old channels were filled when the river was straightened, with the location and quality of that fill unknown. It also notes at least six idle or abandoned oil wells in the city, so ask the soils engineer to check records.
Whether a garage conversion that adds no floor area needs the report is a plan check answer, not a guess. Removing a wall or demolishing more than 100 square feet also requires notice to the South Coast AQMD.
Can I convert a Bellflower garage into an ADU?
Yes, and the City handles it in the same submittal process as a new unit. The ADU application has a box for a garage conversion, and its list of reasons no parking may be required includes that no replacement parking is needed when a garage or carport is converted. The single-family zones otherwise require two enclosed 20 by 20 foot spaces, so expect Planning to review how the conversion fits that rule.
With a median year built of 1966 and 25.5 percent of homes from the 1950s, the garage is often as old as the house. Inspect the slab, the door opening and the wall framing first. A livable unit needs a bathroom, a kitchen, an energy package and its own utility connection.
Records matter. The Housing Element says staff give technical help to owners who want to bring an illegal unit into compliance, and Code Enforcement cases have included illegal garage conversions. State law, in Government Code section 66311.7, limits denial of an ADU built before 2020 without a permit. Our post on garage conversion permit steps shows what a file holds.
How long does an ADU permit take in Bellflower, and what do I submit?
Email the permit technicians at the Building and Safety Division for submittal requirements. The City's handout asks for the building permit application, full plans, structural calculations and energy reports as PDFs, with a vicinity map, site plan, floor, foundation and framing plans, and plumbing, mechanical and electrical plans. A Title 24 energy package is always required, and an LLC or corporation owner must attach a Secretary of State Statement of Information. The handout lists four plan sets even though the City says plan check is electronic, so confirm the format.
State law sets the clock: a completeness answer within 15 business days and a decision within 60 days of a completed application, with deemed approval if the City misses it, under Government Code section 66317. Correction rounds add time.
Fees are where we stop. The handout says development fees apply to ADUs over 750 square feet, while section 17.17.040 says fees are proportional to the main house, and we could not decode the fee sheet's bands, so we print no total. Counter hours differ between City pages, so ask before you drive.
Fire flow, water companies and sewer for a Bellflower ADU
Every ADU is subject to a fire flow form unless Fire Plan Review approves otherwise. The City's form says the permit may issue when the water system delivers at least 1,000 gpm at 20 psi for an hour (500 gpm for half an hour if sprinklered), the structure is under 3,600 square feet, no lot frontage sits more than 450 feet by vehicle path from a hydrant, and the property is outside a Fire Hazard Severity Zone. A sprinklered new detached ADU may sit up to 300 feet from a 20-foot access road, instead of 150.
Four water companies and the City's own system serve Bellflower: Bellflower Home Garden Water Company, Bellflower-Somerset Mutual Water Company, the City's Municipal Water System and Liberty Utilities. The one that signs the form depends on your address, so find yours early. Sewer service comes through the Los Angeles County Consolidated Sewer Maintenance District.
Each ADU installs its own utility connection, subject to a connection fee or capacity charge, unless state law says otherwise, and a separate entrance or utility connection needs an address number from the Director.
ADU photos from Bellflower and nearby communities
Six ADU scenes tied to Bellflower and nearby places such as Lakewood, Norwalk and Downey, from slab and utility trench to finished backyard units. Tap a photo to enlarge it.
What adu construction costs around Bellflower
Our ADU construction page gives regional ranges of about $100,000 to $200,000 for a garage conversion and $200,000 to $400,000 for a detached unit of 400 to 800 square feet, read from studies dated 2018 to 2026; Remodeling magazine's 2025 Cost vs. Value report puts a Los Angeles ADU at $178,536. No Bellflower price study turned up. The ADU cost guide explains the sources. Lakewood, Norwalk and Downey have their own rules: see Lakewood, Norwalk, Downey and Los Angeles, while Paramount, Cerritos and Artesia have separate planning departments. The same lot may also want a room addition in Bellflower or a bathroom remodel in Bellflower, and our subcontractor guide explains who answers to whom on an ADU job.
| 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 |
Bellflower ADU questions, answered
How big can an ADU be in Bellflower?
Up to 1,200 square feet of gross area, attached or detached, under section 17.17.050 of the Municipal Code. State law still requires a city to allow a new detached ADU of at least 800 square feet. A junior ADU is limited to 500 square feet and must be carved from the existing house. Ask Planning how the cap treats garage conversions.
Do I need to provide parking for my ADU in Bellflower if I convert the garage?
Not always. The City's ADU application lists exemptions, including a half mile walk to transit, a unit inside the house or an accessory structure, and no replacement parking when a garage or carport is converted. Where parking applies, state law allows at most one space per ADU or per bedroom, whichever is less. Check the exemption list for your lot with Planning.
How far must an ADU sit from the property line in Bellflower?
We could not find a Bellflower setback for ADUs, because Chapter 17.17 does not restate one and no standards document turned up. State law caps side and rear setbacks at 4 feet for new construction and sets none for conversions of existing structures. Ask Planning in writing which number it applies to your zone and lot.
Does Bellflower allow a junior ADU on a single-family lot?
Yes, the Municipal Code provides for JADUs with conditions: no separate sale, no rental under 30 days, and the owner living in the home or the JADU. State law since 2026 requires owner occupancy for a JADU only when its sanitation facilities are shared with the house, so the two may differ. Ask Planning which reading it applies.
Can I rent out my garage conversion ADU as an Airbnb in Bellflower?
Not for stays under 30 days. Chapter 17.17 requires ADU and JADU rentals to be 30 days or longer, and the owner must record a covenant approved by the City Attorney. An ADU also cannot be sold separately from the main house except under narrow state exceptions. Ask Planning whether a City business license applies to rental income.
How long does it take to build an ADU and get an ADU permit in Bellflower?
State law requires a completeness answer within 15 business days and a decision within 60 days of a completed application, with deemed approval if the City misses the deadline. Residential plan check is posted at about 10 business days, though corrections extend it. For the build itself we plan roughly 3 to 5 months for a garage conversion and 5 to 9 for a detached ADU.
How much does it cost to build an ADU in Bellflower?
Budget about $100,000 to $200,000 to convert a garage and $200,000 to $400,000 for a new detached unit of 400 to 800 square feet. Both are regional ranges from studies dated 2018 to 2026, because no Bellflower price study turned up. Soils work, utility connections and the electrical panel move the total, and your written proposal sets the price.
How much are ADU permits and impact fees in Bellflower?
We could not verify a total. State law bars impact fees on an ADU of 750 square feet or less, and larger units pay in proportion to the main house. The City's handout also lists school fees for projects over 500 square feet. The fee sheet's square-foot bands could not be decoded, so ask for a written fee estimate for your address.
Does Bellflower offer pre-approved ADU plans?
We could not confirm it. The 2022 Housing Element said the City was working on pre-approved ADU plans, but no such program turned up on the City site. Even a pre-approved plan would still need a site plan, a soils report for a new unit and the energy package. Ask the permit technicians whether any City-approved plan set exists today.
Can I convert my garage into an ADU in Bellflower?
Yes. The City's ADU application and handout cover garage conversions in the same process as new units, and no replacement parking is required when the garage is converted. Expect a Title 24 energy package, a bathroom, a kitchen and a separate utility connection. If the garage was converted without a permit, ask Planning about legalizing it first.
Describe your Bellflower ADU idea
Tell us the cross streets, whether you have a garage to convert, the year the house was built and what you want to rent or house, and we will prepare the questions to put to Planning before the visit.