Accessory Dwelling Units (ADUs)

All Accessory Dwelling Units (ADUs) Guides

• Accessory Dwelling Units (ADUs) Knowledge Hub

  Plan an ADU with a homeowner-first hub covering feasibility, property fit, options, budgets, teams, permits, timelines and common mistakes.

• Is an ADU Right for Your Property and Goals?

  Evaluate whether an ADU fits your household goals, property conditions, financial picture and readiness to manage the project.

• ADU vs. Home Addition: Which Is the Better Fit?

  Choose between an independent ADU and an integrated home addition by comparing use, property fit, systems, approvals and long-term needs.

• Detached vs. Attached ADUs

  Compare detached and attached ADUs across privacy, property fit, utilities, construction impact, budget and long-term flexibility.

• Garage Conversion vs. New ADU Construction

  Compare garage conversion and new ADU construction using complete scope, existing conditions, utilities, property fit and long-term use.

• Prefabricated vs. Site-Built ADUs

  Compare prefab and site-built ADUs by jurisdictional acceptance, site fit, installed scope, logistics, contracts and responsibilities.

• How to Evaluate Your Property for an ADU

  Use a practical feasibility framework to investigate jurisdiction, property records, site conditions, access, utilities and existing structures.

• San Diego ADU Requirements and Approval Process

  Understand the City of San Diego ADU approval path, from jurisdiction and property research through permitting, inspections and closeout.

• How Much Does an ADU Cost?

  Understand the property, utility, design, approval and construction factors that shape an ADU's complete project cost.

• How to Build a Realistic ADU Budget

  Build an all-in ADU budget that separates confirmed costs, estimates, allowances, exclusions and unresolved conditions.

• How to Compare ADU Designers and Builders

  Compare ADU designers and builders using consistent scope, deliverables, assumptions, exclusions, credentials and responsibilities.

• Surveys, Engineering and Technical Reports for ADUs

  Understand what ADU surveys, engineering and technical reports answer, when they may be needed and how to scope them.

• The ADU Design and Permit Process

  Follow the ADU process from goals and feasibility through coordinated documents, plan review, permitting, construction and final approval.

• How Long Does It Take to Plan and Build an ADU?

  Plan the complete ADU timeline across feasibility, design, technical work, permitting, procurement, construction and inspections.

• Common ADU Planning Mistakes

  Avoid early ADU assumptions that create redesign, budget pressure, unclear responsibility and preventable schedule delays.

• What Is an ADU Feasibility Study?

  Understand how preliminary property research identifies ADU opportunities, constraints, risks and next steps before full design.

• Financing an ADU

  Compare ADU funding paths, lender requirements, appraisals, construction draws and cash-flow risks before selecting financing.

• ADU Rental Income, Property Value and Financial Expectations

  Evaluate ADU rent, operating costs, financing, property value and long-term financial expectations using realistic scenarios.

• Common ADU Cost Drivers and Budget Surprises

  Identify the site, utility, design, scope and construction conditions that commonly increase ADU budgets.

• Utility Fees, Taxes and Ongoing ADU Expenses

  Plan for ADU property taxes, utilities, insurance, maintenance, reserves and rental operating expenses after construction.

• ADU Water, Sewer and Plumbing Connections

  Evaluate the water, sewer and plumbing conditions that can shape an ADU’s location, foundation, budget, schedule and feasibility.

• ADU Electrical Service, Solar and Energy Planning

  Assess whole-property electrical capacity and coordinate service, panels, meters, solar, equipment and utility requirements before finalizing the ADU.

• Heating, Cooling and Ventilation for an ADU

  Plan a complete ADU mechanical system around climate, enclosure, layout, occupancy, ventilation, equipment space and energy use.

• Foundations, Grading and Drainage for Detached ADUs

  Evaluate soils, slope, drainage, runoff, utilities and access before treating a detached ADU foundation and site plan as final.

• Preparing Your Property for ADU Construction

  Prepare the property for ADU construction with a safe work zone, workable access, protected household areas and clear logistics and communication.

• Living Next to an ADU Construction Project

  Protect household routines, access and safety while construction takes place beside the occupied main home.

• Access, Deliveries, Staging and Neighbor Impacts

  Plan a workable construction route and staging strategy that protects the home, neighbors and public access.

• Common ADU Change Orders and Unexpected Conditions

  Use a documented change-order process to evaluate concealed conditions, owner decisions and their effects on price and schedule.

• ADU Quality-Control Milestones

  Check work at the milestones when details remain visible and corrections are still practical.

• ADU Final Inspections, Closeout and Occupancy

  Coordinate required final approvals, resolve corrections and collect a complete handoff package before treating the ADU as finished.

• What Is a Junior ADU?

  Learn the defining features, limitations and planning implications of a California Junior Accessory Dwelling Unit.

• ADU Site Planning: Access, Privacy and Outdoor Space

  Evaluate the complete property relationship before choosing where an ADU should sit.

• ADU Zoning, Setbacks, Height and Lot-Coverage Rules

  Map the regulatory building envelope before committing to an ADU size, configuration or stock plan.

• California ADU Laws: What Homeowners Need to Know

  Understand the statewide ADU framework while preserving the need for current, property-specific local verification.

• Coastal, Historic and HOA Considerations for ADUs

  Identify special review layers early without assuming they automatically prohibit—or automatically allow—an ADU.

• ADU Parking Requirements and Transportation Considerations

  Separate legal parking requirements from the practical transportation and access needs of the property.

• Fire Access, Separation and Sprinkler Considerations for ADUs

  Treat access, separation, sprinklers and wildfire conditions as related but distinct parts of ADU feasibility.

• How to Define the Scope of an ADU Project

  Create a complete scope framework before comparing prices or committing to design and construction.

• How Big Should Your ADU Be?

  Use the smallest size that fully supports the intended use rather than defaulting to the maximum allowed area.

• ADU Floor Plans: Making a Small Space Work Well

  Evaluate compact ADU layouts by function and daily use rather than square footage alone.

• Designing ADU Kitchens for Small Spaces

  Coordinate the complete small kitchen before selecting finishes or sacrificing essential function.

• Designing ADU Bathrooms for Comfort and Efficiency

  Balance compact dimensions with comfort, durability and future adaptability in an ADU bathroom.

• ADU Storage and Built-In Space Planning

  Integrate storage early so a compact ADU remains useful without becoming rigid or cluttered.

• Natural Light, Privacy and Views in an ADU

  Use the complete property relationship to place openings that improve comfort without sacrificing privacy.

• Sound Control Between an ADU and the Main Home

  Reduce avoidable noise conflicts by coordinating the property, floor plan, assemblies and construction details as one acoustic strategy.

• Designing an ADU for Long-Term Flexibility

  Plan a durable, adaptable ADU around likely use sequences, accessible circulation and future-ready systems.

• Who Should Be on Your ADU Project Team?

  Build the ADU team around the property, delivery method and clearly assigned responsibilities.

• Architect, Designer or Design-Build for an ADU?

  Choose an ADU delivery approach by comparing scope, independence, coordination, pricing and property-specific complexity.

• What Can You Use an ADU For?

  Define the intended ADU use early because it shapes feasibility, design, operations and long-term responsibilities.

• Preparing an ADU for Family Members

  Plan the living arrangement as carefully as the unit so family housing remains supportive, private and workable.

• Preparing an ADU for Long-Term Rental Use

  Treat a rental ADU as both a home and an ongoing operating responsibility before a tenant moves in.

• ADU Insurance, Maintenance and Recordkeeping

  Protect the ADU investment with current coverage, scheduled maintenance and a complete record of the unit and its systems.