The following provides guidance to the applicant by outlining the minimum Building Division submittal requirements to be part of the City of Downey’s AB1332 Pre-Approved ADU program.

This program will require two different plan submittals. One by the design professional for their plans to be include in the pre-approved ADU plan program. The second by the homeowner; the pre-approved plans are only about 80% complete and will always require property-specific modifications. In addition to the building plans, site-specific land use information will need to be completed. Once the property owner selects a pre-approved plan, they will work directly with that design professional to prepare construction documents that represent their site-specific factors.

 Important: Once the homeowner/applicant has obtained approved for submittal, the applicant will need to submit a New Address Request: Complete this step prior to plan submittal to avoid delays.

1. A separate submittal, application, and plan check fee is required for each standard plan.

2. When prompted to enter an address, use AB1332

3. For Project Description, indicate that you are submitting a “Standard Plan under the Pre-Approved ADU Plans Program” then provide the project description.

The initial submittal process for a Standard Plan ADU under the Pre-Approved ADU Plans Program will be very similar to a normal plan submittal.

1. Applicant must obtain Planning “OK to submit/pre-approval”.

2. Plans will be submitted to the Building Division.

3. Building Division will route plans to Planning, Public Works/Engineering, and Fire for concurrent reviews.

• Once all departments have completed their reviews, the applicant will be notified, and the following will be posted on the city’s website:

• Designer contact information

• ADU description provided by applicant

• Renderings provided by applicant

• Simplified plans and elevations provided by applicant

• Photos: provided by applicant

Please Note: Hand-written information will not be accepted

General Requirements 

• City of Downey- Permit Application A review and a pre-approval (“an OK to submit”) by the Planning Division is required prior to Building Division submittal. Your application form must include all proposed work, including demolition, engineering, site improvements, etc. and is subject to verification and adjustment during plan review.

• PLANS: Four (4) complete sets of plans, printed on 24” X 36” sheets. Plans must follow standard drafting conventions and be complete. Typically, plan scale is 1/8” for site plan & plot plan. 1/4” scale for floor plan, elevations, sections, etc.

• SOILS REPORT: Two (2) copies if required. See Downey handout titled “When a soils report is required”.

• STRUCTURAL CALCULATIONS: Two (2) copies of the supporting calculations, wet stamped and signed, unless waived by the Building Official.

• FIRE SPRINKLERS: Indicate if the existing building is protected by an automatic sprinkler system. Projects that require a new Fire Sprinkler System to be installed shall have the cover sheet notated “FIRE SPRINKLERS REQUIRED”. Fire sprinklers can be a deferred submittal. Please note, all deferred submittals shall be approved by the city prior to framing inspection. Framing will not be approved until all deferred submittals have been approved.

• TITLE 24 ENERGY ANALYSIS: Two (2) sets of 8 ½ x 11” completed energy calculations is required for submittal and shall be made part of plans.

• Design shall be provided with options for installation fire rated walls.

• Design shall be provided with options for exterior finish materials to ensure architectural compatibility with primary dwelling unit and surrounding neighborhood.

Plan Information

• Please reference our 2022 CRC Standard Plan Check Correction List and Pre-approved ADU submittal checklist for additional requirements and information.

• A complete “Project Description” and “Scope of Work” must be on the cover sheet of the plans. The plan description/ scope of work must match the application description and include breakdown of square footage (example: new, remodeled, garage, porch, etc.)

• Residential plans may be produced (drawn) by a licensed Architect or Engineer, the Property Owner/Builder, Design Consultant, licensed Contractor or other qualified person. Plans that are not legible may be rejected prior to plan review. All plans shall be signed by the person(s) preparing the plan.

• The California Energy Code generally requires solar photovoltaic systems to be installed on all new low- rise residential structures. As such, PV systems are required for all of the ADU structures regardless if the ADU is to be a primary dwelling or accessory to a primary dwelling. PV plans will be required to be submitted along with the other required plans and documents. Energy Code requirement to provide solar panels if the unit(s) is a newly constructed, non-manufactured, detached ADU. Per the California Energy Commission (CEC), the panels can be installed on the ADU or on the primary dwelling unit. ADU’s that are constructed within existing space, or as an addition to existing homes, including detached additions where an existing detached building is converted from non-residential to residential space, are not subject to the Energy Code requirement to provide solar plans

• Deferred Submittals shall be clearly noted on the cover sheet and will be required to be submitted, approved and permitted prior to the framing inspection.

• Documents for deferred submittals shall include a statement by the architect or engineer of record in responsible charge indicating that the deferred submittal documents have been reviewed and found to be in general conformance to the design of the building.

• Project address.

• Owner’s name and address.

• Designer / Architect / Engineer of Record contact information.

• Name, address and telephone number of person who prepared the plans.

• The Legal description (A.P.N.).

• Occupancy group.

• Type of Construction.

• Floor Area calculations, including existing and new areas.

• Site area and % of coverage.

• Note if a fire sprinkler system is installed

• Show the proposed floor plan that includes the existing walls to remain, demolished walls, unless a detailed demolition plan is included, and the new walls. Include a wall legend for the existing walls to remain, walls to be demolished and new walls shall be provided. Existing walls with structural upgrades affecting the foundation or the lateral support (shear) are considered new walls. Existing walls with the drywall removed are considered part of the area of renovation.

• Mechanical, plumbing and electrical details may be included on the floor plan or a separate utility plan sheet for review. While not requiring complete single-line drawings, the plan shall include the following:

• Locations of heating, cooling and ventilating equipment.

• Mechanical equipment schedule identifying the equipment manufacturer’s name, model number, capacity, etc.

• Kitchen ventilation system (range hood) complying with the 2022 Title 24 and ASHRA 62.2 standards.

• Bathroom Ventilation complying with the 2022 Title 24 and ASHRA 62.2 standards.

• Whole house ventilation, required for projects 1,000 sq. ft. or more.

• Location of the plumbing fixtures including the water heater.

• Location of condenser

• Electrical panel schedules and load schedules if required.

• Show the location of all receptacles, switches and lights, and use a legend to identify types.

• Smoke and Carbon Monoxide Alarms are required and shall be notated on the plan.

• Detail on the cover sheet, any special conditions or requirement notated in the energy analysis. (i.e.; HERS testing, Cool Roof, etc.)

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