ADU Builder in Bellflower, CA: Permits, 2025 Code and Costs

Does Bellflower have an ADU ordinance on file with HCD?

The City of Bellflower ADU ordinance on file with HCD was adopted in 2020 and is the City of Bellflower Ordinance No. 1401, which HCD found on April 1, 2022 did not comply with state law on the discretionary review and minimum size requirements. The HCD Technical Assistance letter dated December 5, 2025, hosted on hcd.ca.gov, states the most recent ADU ordinance on file for the City of Bellflower is from 2020 and that numerous changes to State ADU Law since 2020 may warrant an update. The HCD letter lists 13 specific state law items that have changed since the 2020 ordinance, including Gov. Code 66317(a)(2)(A) on the 15 business day completeness determination, Gov. Code 66317(d)(1) on the 60 business day appeal clock, Gov. Code 66311.5 on the 750 square foot impact fee cliff, Gov. Code 66313(d) on the 500 square foot JADU interior cap, Gov. Code 66321 on the 850 and 1,000 square foot minimum floors, and Gov. Code 66315 on the prohibition against deed restrictions and HOA third party review. Bellflower property owners work from the 2020 Bellflower ordinance plus the current State ADU Law, with state law controlling any conflict.

What construction documents does Bellflower require for an ADU?

The City of Bellflower Residential ADU Handout #13, hosted on bellflower.ca.gov, lists the construction documents the City requires for an ADU permit submittal: four sets of architectural and structural plans, a vicinity map, a site plan, an existing floor plan and proposed floor plan, a foundation plan, a soils report with liquefaction study required for additions of 750 square feet or greater, new dwelling units, and additions of a second story, roof and floor framing plans, structural and construction details and cross sections, structural calculations if required, plumbing, mechanical, and electrical plans, and Title 24 energy calculations and forms. The same Handout #13 states that all plans and permit applications are required to be submitted electronically in PDF format, that a Title 24 energy compliance package is always required, and that construction documents must be prepared by registered licensed professionals when the design does not meet conventional construction standards. New construction of a detached structure may require grading plans and review.

How long does the Bellflower ADU plan check take?

The City of Bellflower Plan Review and Submittal page, hosted on bellflower.ca.gov, states that residential projects take approximately 10 business days for plan check and commercial projects take approximately 15 business days. The same page states that all new and currently submitted plans under the 2022 code must be approved and permits issued by March 30, 2026, and that otherwise compliance with the new 2025 codes will be required for approval and issuance. Handout #13 confirms that the 2025 California Residential Code, Mechanical Code, Plumbing Code, Electrical Code, Energy Code, Green Building Standards Code, Fire Code, and the City of Bellflower Regulations and Ordinances are the controlling code set. State law in Gov. Code 66317(a)(3) still applies, so if the City does not act on a completed application within 60 days the application is deemed approved.

What other agency approvals does a Bellflower ADU trigger?

The City of Bellflower Residential ADU Handout #13, hosted on bellflower.ca.gov, lists three other agency approvals that attach to ADU projects. Every ADU is subject to a Fire Flow 195 form unless approved by the Fire Plan Review. Development fees apply for ADUs over 750 square feet. An AQMD notification is required for projects that include any removal of walls or demolition work over 100 square feet, with no exception. School development fees apply to all projects over 500 square feet. The Handout also notes that Bellflower recommends hiring an appropriately licensed State of California contractor and registered licensed professionals to design and provide all necessary documentation for the submittal and review process.

How much does a Bellflower ADU cost?

L Square publishes configured model prices on the cost guide page hosted on lscontractor.com at $180,000 for the 600 square foot Model 600, $240,000 for each of the 800 square foot Models 800A and 800B, $295,000 for each of the 1,000 square foot Models 1000A and 1000B, and $354,000 for the 1,200 square foot Model 1200. These are model prices, not a final lot total. Bellflower lots also carry the Building and Safety plan check fee set by the City fee schedule, the proportional impact fee on ADUs over 750 square feet under the Bellflower Development Impact Fee Annual Report for Fiscal Year 2022-23 and Gov. Code 66311.5, school district fees where the project exceeds the district threshold, and any utility and connection fees from the providers named in the City application materials. The DIF report lists single family at $21,839 per dwelling unit, multi-family at $18,288 per dwelling unit, and ADUs larger than 750 square feet at a fee proportional to the primary unit.

What should a Bellflower homeowner check before starting an ADU?

Before applying, confirm four items on your property. First, identify the lot zone, lot dimensions, and any easements, because the City ADU Application asks for them on the cover page. Second, confirm the size of the existing primary dwelling, because the proportional impact fee under Gov. Code 66311.5 for ADUs over 750 square feet is calculated against the primary dwelling square footage. Third, check the school district boundary and the school fee threshold, because the City handout applies school fees to projects over 500 square feet. Fourth, plan the submittal electronically, because the Plan Review page on bellflower.ca.gov requires PDF submittal to the Planning Division by email for preliminary plan review, then PDF submittal to the Building and Safety Division via a Dropbox link with the Planning Division Assignment Sheet attached. The state 60 day clock in Gov. Code 66317(a)(3) starts at receipt of a complete application, and the City must issue a completeness determination within 15 business days under Gov. Code 66317(a)(2)(A).

Official Bellflower ADU sources

• The City of Bellflower Residential ADU Handout #13, hosted on bellflower.ca.gov, states that the controlling code set is the 2025 California Residential Code, Mechanical Code, Plumbing Code, Electrical Code, Energy Code, Green Building Standards Code, Fire Code, and the City of Bellflower Regulations and Ordinances, and that the Handout was Updated 09/21/2026. Official source
• The HCD review of the Bellflower ADU ordinance dated April 1, 2022, hosted on hcd.ca.gov, identifies the City of Bellflower ADU ordinance as Ordinance No. 1401 adopted September 14, 2020, and states HCD found the Ordinance did not comply with state law because the permitting process was impermissibly vague and could allow subjective or discretionary review. Official source
• The City of Bellflower Plan Review and Submittal page, hosted on bellflower.ca.gov, states that all new and currently submitted plans under the 2022 code must be approved and permits issued by March 30, 2026, otherwise compliance with the new 2025 codes will be required, and that residential plan check takes approximately 10 business days and commercial plan check takes approximately 15 business days. Official source
• The HCD Technical Assistance letter dated December 5, 2025, hosted on hcd.ca.gov, addressed to the City of Bellflower Director of Planning and Building Services, states the most recent ADU ordinance on file for the City of Bellflower is from 2020, and lists 13 state law changes since 2020, including Gov. Code 66317(a)(2)(A), 66317(d)(1), 66311.5, 66313(d), 66321, 66315, and 66326(d). Official source
• The City of Bellflower Development Impact Fee Annual Report for Fiscal Year 2022-23, hosted on bellflower.ca.gov, lists Park Facilities Fees at $21,839 per single family dwelling unit, $18,288 per multi-family dwelling unit, and a fee proportional to the primary unit for ADUs larger than 750 square feet, reported annually under Government Code Section 66006. Official source
• California State ADU Law under Gov. Code 66317(a)(3) requires the permitting agency to act on a complete application within 60 days, after which the application is deemed approved, and Gov. Code 66311.5 prohibits impact fees on ADUs up to 750 square feet of interior livable space and requires proportional impact fees above 750 square feet measured against the primary dwelling square footage. Official source
• California State ADU Law under Gov. Code 66321 sets the minimum floors a city must permit at 850 square feet for studios and one bedroom ADUs and 1,000 square feet for ADUs with two or more bedrooms, with a 4 foot side and rear yard setback and 16 foot height, and a 500 square foot JADU interior cap under Gov. Code 66313(d). Official source