Pre-Approved ADU Plans San Diego | Costs, Permits & Plan Options
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Pre-Approved ADU Plans in San Diego

Use a standard plan when it fits the property, not just because the drawing is already approved.

Pre-approved ADU plans can reduce design work and shorten agency review, but they are not universal permits. Every San Diego property still needs a site-specific application addressing zoning, placement, foundation, utilities, drainage, fire conditions, coastal requirements and construction access.

Review pre-approved plan options Check property feasibility
30-day review City review period for a complete qualifying pre-approved plan application
Not permit-ready Site plan, placement, utilities, foundation and local conditions remain
Best fit Standard lots where the plan can be used with limited modification

The City of San Diego currently accepts specified pre-approved plans from the County of San Diego, City of Chula Vista and City of Encinitas. These plans can simplify the building-design portion of the application, but the owner must still prove that the selected model works on the actual parcel.

Direct definition: "pre-approved" means the standard building design has received advance review. It does not mean construction can begin, the plan automatically fits the property or the agency has approved the site, utilities, foundation and local development conditions.

What pre-approved ADU plans actually include

A pre-approved plan is a repeatable architectural and structural design reviewed in advance by a local building agency. The plan set may include floor plans, elevations, sections, framing, foundation concepts, structural details, code notes and other standard construction information.

The amount of completion varies by program. San Diego County describes its dwelling-unit plans as approximately 85% complete because owners must add project-specific information. Other programs may require licensing, adaptation by the original designer or additional consultant documents.

1

Standard building design

The repeated unit layout, exterior elevations, typical sections, framing approach and code details have already received agency review within the program's stated limits.

2

Site-specific insertions

The property owner or design team must add the site plan, address, parcel data, setbacks, utility routing, orientation and other information unique to the parcel.

3

Agency permit application

The complete adapted package is submitted to the jurisdiction that controls the property. Approval and permit issuance are still required before construction begins.

Which pre-approved plans does the City of San Diego accept?

The City's current ADU program page identifies three public plan sources that applicants may use for a pre-approved ADU permit application:

  • County of San Diego Standard ADU Plans
  • City of Chula Vista Standard ADU Plans
  • City of Encinitas Permit-Ready ADU Plans

This list can change as agencies add plans or private applicants obtain pre-approval. Verify the current City list and provider requirements before paying for adaptation, engineering or licensing.

The City accepts the plan, not every possible modification

Pre-approval normally applies to the reviewed version of the design. Moving structural walls, changing the footprint, altering major openings, adding a second story or redesigning the roof can remove the benefit of the pre-approved review.

Cosmetic selections such as cabinets and finishes are usually easier to vary than structural dimensions, exterior openings and building-system assumptions.

Public pre-approved plan sources are not interchangeable

Plan source What to verify San Diego application issue
County of San Diego Available models, plan completeness, checklist requirements, orientation, foundation limits and current files. The County states its plans are approximately 85% complete. Site-specific information must be added.
City of Chula Vista Available sizes, designer or licensing terms, permitted modifications and current City of San Diego acceptance. A Chula Vista standard plan used in San Diego still needs to meet City of San Diego submittal requirements.
City of Encinitas Plan-provider contact, license cost, adaptation services, drawing format and site-specific deliverables. Permit-ready design review does not replace City of San Diego site and development review.
Private pre-approved plan Whether the exact plan appears on the agency's current list, who owns it and what the license includes. The City instructs applicants to contact the ADU provider directly regarding the cost to license a plan.
Before selecting a plan: confirm the exact model name, plan version, provider contact, licensing terms and whether the property's jurisdiction currently accepts it as pre-approved.
Pre-approved ADU architectural drawings prepared for San Diego permit review

How the 30-day City review works

City of San Diego Information Bulletin 400 states that applications using pre-approved plans are subject to a 30-day review. The application must still be complete and comply with applicable San Diego Municipal Code development regulations.

The shorter review does not eliminate:

  • Application completeness review
  • Property-specific zoning review
  • Site-plan and setback verification
  • Foundation and soils coordination
  • Fire, coastal or historic review when applicable
  • Utility and drainage information
  • Correction responses for missing or conflicting documents
  • Permit fees and administrative requirements
Timing distinction: a 30-day review period is not the same as a guaranteed permit in 30 days. An incomplete package, unresolved corrections, owner changes or outside-agency requirements can extend the practical schedule.

What remains site-specific with a pre-approved ADU plan

The greatest misunderstanding is that the downloaded or licensed plan is ready to submit unchanged. The property package may require substantial work even when the standard building has already been reviewed.

Site-specific item What must be shown or verified Potential effect on the standard plan
Property survey Boundary, corners, existing structures, walls, easements and elevations when needed. The apparent yard may not match legal boundaries or the required setback envelope.
Site plan Parcel, setbacks, structures, access, utilities, drainage, parking and proposed ADU orientation. The plan may need rotation or mirroring if those changes are allowed by the provider and agency.
Foundation Soils, slope, bearing, slab or raised foundation, retaining conditions and local engineering. A standard slab may not work on fill, expansive soil, a hillside or near a retaining wall.
Sewer or septic Connection location, elevation, pipe slope, cleanouts, pumping and septic capacity where applicable. Wet-room placement or building location may be inefficient for the actual sewer route.
Water Supply route, meter and district requirements, pipe sizing and trench coordination. Long runs or conflicts with hardscape can change cost and placement.
Electrical Service size, panel capacity, load calculations, trench or overhead path and utility requirements. An older service may require a panel or service upgrade before the all-electric ADU can operate.
Drainage Roof runoff, downspout discharge, grading, impervious area and protection of adjacent property. The plan's roof design may be standard, but discharge locations must work on the parcel.
Fire conditions Hazard mapping, canyon exposure, access, addressing, materials, openings and sprinklers when applicable. Openings, vents or exterior assemblies may need site-specific upgrades or relocation.
Coastal review Coastal Overlay Zone status and applicable local coastal approval process. A plan accepted inland is not automatically exempt from coastal requirements.
Construction access Equipment, concrete, material delivery, demolition, staging and occupied-site protection. A plan may fit legally but cost more to build because the rear yard is difficult to access.

Pre-approved ADU plan process in San Diego

The most efficient sequence is to select the standard plan after feasibility, not before it.

Confirm the property jurisdiction

Determine whether the parcel is in the City of San Diego, unincorporated County or another incorporated city. Plan acceptance, permit portals and submittal requirements differ.

Complete an ADU feasibility review

Check zoning, overlays, setbacks, buildable area, easements, legal structures, fire, coastal, sewer, septic, water, electrical, drainage and construction access.

Compare available pre-approved models

Select by exterior dimensions, bedroom count, accessibility, window orientation, entry location, mechanical layout and how well the wet areas align with the property's utility route.

Confirm license and modification rules

Contact the plan provider. Determine the license cost, included documents, adaptation services, design ownership, allowed changes and responsibility for correction responses.

Prepare the site-specific package

Add the site plan, parcel data, zoning information, orientation, utilities, foundation adaptation, energy documents and required jurisdiction forms.

Submit the building permit application

Upload the complete plan set and supporting documents through the correct agency portal. Identify the plan as an accepted pre-approved design using the required naming or reference information.

Respond to site-specific corrections

Coordinate planning, structural, fire, stormwater, utility and other comments without making unnecessary changes to the pre-approved building design.

Obtain the permit and build from stamped plans

Pay issuance fees, obtain approved documents and schedule inspections in the required sequence. Field changes can require revised plans even when the original design was pre-approved.

Benefits of using pre-approved ADU plans

1

Reduced building-design work

A substantial portion of the architectural and structural package may already be complete, limiting the amount of original design required for a standard project.

2

Shorter City review target

The City of San Diego identifies a 30-day review for complete applications that use qualifying pre-approved plans, compared with the general state review framework for standard ADU applications.

3

Known repeatable layout

Owners can evaluate a defined floor plan, dimensions and exterior before paying for a full custom design.

4

Easier early estimating

A complete standard model allows contractors to compare scope more consistently than a verbal square-footage request or rough sketch.

5

Fewer design decisions

Owners who prioritize speed and function can avoid months of changing room sizes, exterior styles and structural layouts.

6

Lower redesign risk

When the model fits the lot without structural changes, the core design has already been reviewed within the accepting program.

Limitations owners should understand

Pre-approved plans work by standardization. The more the owner changes the plan or forces it onto a difficult property, the less time and cost advantage remains.

  • The plan may not fit the actual buildable envelope.
  • Window and entry locations may create poor privacy.
  • The standard foundation may not match the soils or slope.
  • Utility locations may make the plan expensive to connect.
  • Exterior design may not match the main house or neighborhood.
  • Provider licensing and adaptation fees may apply.
  • Major modifications can require normal plan review.
  • Site engineering and permit fees remain.
  • Coastal, fire and historic conditions remain.
  • Construction cost is not pre-approved or guaranteed.
ADU construction using approved architectural and structural plans

When a pre-approved ADU plan is usually a strong choice

Flat suburban lot

A reasonably level backyard with clear setbacks, public sewer, practical side access and simple utility routing is the strongest standard-plan candidate.

Rental-focused project

Owners prioritizing durable bedrooms, efficient kitchens, laundry, storage and predictable construction may benefit more from a standard layout than custom architecture. See our ADU rental income guide for what features most affect rent.

Parent or family housing

A single-story plan with practical circulation can work well when the selected model meets accessibility, privacy and caregiving needs.

Owner accepts fixed dimensions

The savings are strongest when the footprint, wall locations, roof, doors and windows can remain substantially as reviewed.

Clear utility route

Standard plans work better when the kitchen, bathroom and electrical equipment can connect without long, obstructed or uphill runs.

Speed matters more than uniqueness

A homeowner who wants a functional permitted unit quickly may value certainty more than a custom exterior or highly tailored room arrangement.

Custom design is not automatically more expensive overall

A custom plan can reduce construction cost when it avoids retaining walls, shortens utility runs, preserves mature landscaping, protects the main home's privacy or uses an irregular area more efficiently.

Paying more for design can be rational when the site adaptation saves substantially more during construction or protects the property's long-term value.

When a custom ADU plan is usually better

  • The lot is narrow, triangular, curved or highly constrained.
  • The building area is sloped or requires retaining walls.
  • The property is coastal, historic or architecturally significant.
  • A canyon or fire condition controls openings and placement.
  • The ADU must match a luxury or highly visible main house.
  • The owner needs unusual accessibility or multigenerational features.
  • A second story, garage-top unit or complex attachment is proposed.
  • The wet rooms must be placed around a difficult sewer route.
  • Privacy requires exact window, courtyard or entry design.
  • The owner wants a larger unit or program not available in standard plans.

Pre-approved versus custom ADU plan costs

A pre-approved plan can reduce architectural design fees, but the correct comparison includes every required service and the construction consequences of fitting the plan to the site.

Cost category Pre-approved plan Custom plan
Base architectural design Usually lower because the standard building has already been designed. Higher because the plan is created for the owner and property.
Plan license May be free through a public program or subject to provider licensing fees. Typically included in the project design agreement and limited to the specific property.
Site plan Still required. Still required.
Survey Required when site conditions or agency rules make it necessary. Same property-driven requirement.
Foundation adaptation May require added engineering when the standard detail does not fit the site. Designed for the site from the beginning.
Energy documents May require project-specific updates or verification. Prepared for the selected design and orientation.
Utility design Site-specific and not eliminated by pre-approval. Site-specific and coordinated with the custom layout.
Permit fees Government fees still apply. Government fees still apply.
Construction Can be efficient on a standard lot but expensive if the plan forces poor placement or site work. Can reduce difficult site work by optimizing footprint, utilities and access.
Review time Potentially shorter when the exact accepted plan is submitted as a complete package. Normal ADU review process unless another expedited path applies.
Accurate comparison: request a scope that separates plan licensing, site design, survey, engineering, energy, permit management, government fees, utility work and construction.

How to choose the correct pre-approved floor plan

Do not select solely by bedroom count or total square footage. A good model should fit how the property works.

Exterior footprint

Compare the exact length and width with the realistic setback envelope, not the full visible yard.

Entry orientation

The entrance should have a practical path from the street without directing occupants through the main home's private patio.

Window placement

Check direct views into the main house and neighboring bedrooms. Mirroring may help only when permitted.

Wet-wall location

Kitchens, bathrooms and laundry should be located near the best sewer and water path whenever possible.

Mechanical equipment

Confirm space for heat-pump equipment, water heating, electrical panels and required clearances without blocking access.

Storage and furniture

Evaluate real bed, sofa, dining, closet, laundry and circulation dimensions. A compact plan must still work for long-term occupancy.

San Diego location and property considerations

Clairemont and Mira Mesa

Many lots can work well with standard one-story plans, but sewer location, overhead or underground power, backyard slope and side-yard access still require verification.

North Park and urban neighborhoods

Compact lots, older garages, alley access, historic questions, existing additions and privacy often make footprint dimensions more important than total plan square footage.

La Jolla and beach communities

Coastal review, limited staging, architectural visibility, corrosion exposure, tight lots and property value may justify more customization than a standard plan provides.

Point Loma and canyon lots

Grade, retaining walls, fire exposure, drainage and difficult rear-yard access can remove the cost advantage of a standard slab-on-grade plan.

Chula Vista, La Mesa and Santee

Larger suburban lots can support standard plans efficiently, but the owner must use the rules and permit process of the city where the property is located.

Unincorporated County

County plans are designed for use in unincorporated areas, but septic, wells, fire districts, grading, driveway access and rural utility distances can require substantial property-specific work.

Common pre-approved ADU plan mistakes

Downloading plans before feasibility

Owners become attached to a model before confirming whether it fits the legal building area or utility route.

Assuming free means complete

Public plan files may be free while site adaptation, engineering, energy documents, licensing, permits and construction remain substantial.

Ignoring plan ownership

Some accepted plans require direct contact with the provider and a license before they can be used on a specific property.

Changing structural walls

Major footprint, roof, opening and framing changes can turn a pre-approved plan into a custom review.

Using fences as boundaries

A plan that appears to fit between fences may violate the legal setback if the fences do not follow the property lines.

Forgetting utility equipment

The building footprint may fit while heat pumps, panels, water heaters, meters and required clearances do not.

Selecting by exterior appearance

A visually attractive plan can be inefficient if the kitchen and bathroom face away from the sewer and water.

Assuming 30 days means issuance

The shorter review applies to a complete qualifying package. Corrections and external requirements still take time.

Ignoring construction access

Standard plans do not account for hand-carried materials, pump distances, occupied yards or blocked side access.

Choosing too small

Reducing square footage can save construction cost, but poor storage, laundry and furniture layout can reduce rental and family usefulness.

Choosing too large

A larger plan can consume the main house's yard, increase utility load and create privacy issues without proportionate rent or family benefit.

Not confirming the current list

Plan availability and agency acceptance can change. Verify the program immediately before design and submission.

Official pre-approved ADU plan resources

Use the current agency pages and verify the exact plan version before starting a permit package.

City of San Diego ADU Program

Current City ADU rules and the accepted pre-approved plan sources.

Open City ADU page

City Information Bulletin 400

Permit guidance, 30-day pre-approved plan review and provider licensing notice.

Open Bulletin 400

County Standard ADU Plans

County dwelling-unit plans, plan files, checklist and project-specific completion guidance.

View County plans

City Planning ADU Toolkit

City planning links to standard and permit-ready plans accepted by San Diego.

Open planning toolkit

California HCD ADU Handbook

Current statewide ADU law and pre-approved plan program requirements.

Open HCD handbook

San Diego ADU Permitting

Our detailed guide to site plans, corrections, fees, technical review and inspections.

Read the permit guide

Pre-approved ADU plan FAQs

What does "pre-approved" mean for an ADU plan?

It means the local agency has reviewed the standard building design in advance. The property-specific application, site plan, placement, utilities, foundation and applicable local requirements still need approval.

Which plans does the City of San Diego currently accept?

The City currently identifies County of San Diego Standard ADU Plans, City of Chula Vista Standard ADU Plans and City of Encinitas Permit-Ready ADU Plans. Verify the list before selecting a model.

Are County of San Diego ADU plans accepted inside the City of San Diego?

The City lists County standard plans as accepted pre-approved plans. The package must still satisfy City submittal requirements and City development regulations for the specific parcel.

Are the County ADU plans completely finished?

The County states that its plans are approximately 85% complete. Owners must add the project-specific information identified in the County checklist and guidance.

Does a pre-approved plan cost nothing?

Some agency plan documents may be available without charge. That does not eliminate provider licensing, site design, survey, engineering, energy, permit, utility and construction costs.

Do I need to contact the plan designer?

The City advises applicants to contact the ADU provider directly to determine the cost to license the plan. Provider involvement may also be required for adaptation, permitted changes and correction responses.

Can I change the floor plan?

Minor nonstructural selections may be possible, but moving walls, changing dimensions, openings, roof form or structural elements can remove the pre-approved benefit. Confirm changes before purchasing or submitting.

Can the plan be mirrored?

Some programs may allow a mirrored version while others treat it as a separate reviewed option. Confirm that the exact mirrored configuration is accepted and that all structural and energy documents remain coordinated.

Do I still need a site plan?

Yes. The permit application must show the proposed ADU on the property with setbacks, existing structures, access, utilities, drainage and other required site information.

Do I still need a survey?

Survey requirements depend on the agency and property. A survey is especially important when the building is close to setbacks, easements, retaining walls, slopes or uncertain property lines.

Does the standard foundation work on every San Diego lot?

No. Soil, slope, fill, expansive conditions, retaining walls and drainage can require site-specific foundation engineering or a different foundation system.

Are utilities included in the pre-approved plan?

The plan may show interior plumbing and electrical layouts, but actual sewer, water, power and communication routes are property-specific and must be coordinated with the site and utility providers.

Can I use a pre-approved plan in the Coastal Overlay Zone?

The standard design may be usable, but coastal status and any required coastal approval remain site-specific. Verify the applicable process before relying on the shorter building review.

Can I use a pre-approved plan on a hillside lot?

Possibly, but standard plans offer the greatest value on simpler sites. Hillside properties often require custom foundations, retaining walls, drainage, access planning and plan modifications.

Does the City guarantee a permit in 30 days?

The City states that qualifying pre-approved applications are subject to a 30-day review. A complete package and compliance with applicable regulations are still required, and corrections can extend the schedule.

Is a pre-approved plan always cheaper than custom design?

No. It usually reduces initial design work, but a poor fit can increase foundation, utility, retaining-wall, drainage or privacy-related costs. Compare total project cost rather than architectural fees alone.

Can I use the plan for a garage conversion?

Most detached standard plans are intended for new construction. Garage conversions require documentation and engineering based on the actual existing garage.

Can a pre-approved plan be used as a primary house?

Some County dwelling-unit plans may be usable as an ADU or single-family dwelling in unincorporated County areas, subject to the County program and property requirements. Confirm the intended use with the jurisdiction.

What should I do before choosing a plan?

Complete a feasibility review, identify the realistic building envelope, confirm utilities and site risks, then compare accepted models by dimensions, orientation, layout and provider terms.

What happens after I choose the model?

License or obtain the plan, prepare the property-specific site and engineering documents, submit the complete permit application, answer corrections and obtain the issued permit before construction.

Find the pre-approved ADU plan that fits your property, utilities and budget.

We compare accepted plan models against the actual San Diego parcel, adapt the site-specific package and coordinate the project through permitting and construction. Pre-approved plans are best suited for detached ADUs on straightforward suburban lots. For total project costs, see our ADU cost guide. Financing options are covered in our ADU financing guide. For a planning overview, download the ADU handbook.

Review your ADU plan options