Step 4

Step 4: Costs

How much will it cost to build an ADU and where will the money come from? At this stage of the process, detailed cost estimates, budgets, and financing strategies are created to help you get a firm understanding on the financial realities of building an ADU. Designing and budgeting for an ADU go hand-in-hand.

Action Items:

  • Create a detailed cost estimate

  • Create a detailed budget and financing strategy

  • Secure finances to fund the development of the desired ADU(s)

How Much Does It Cost to Build an ADU?

Cost estimates for ADUs vary widely depending on the on-site conditions, construction style, and materials and finishes. A detailed cost estimate will likely require the consultation of a contractor. Obtaining a detailed cost estimate is necessary to help determine your budget, and how much financing is desired.

This section provides a very general guide to understanding development costs.

Overall Development Costs

Project costs will vary depending on the type of ADU (e.g. detached, attached, modular, etc.) being constructed. Typically, 80% of the total project budget costs can be expected for construction (materials and labor), with another 20% for consulting, design and permitting fees. Typically, the longer the construction timeline, the more costs incurred.

City Permit and Development Fees

The City collects fees for the review of each ADU application. The Planning Application fee is a flat rate and can be found on the application form. The Building Plan Review fee may vary for each project and includes review fees for other City Departments and Divisions, such as Public Works and the Department of Utilities. These fees only cover the costs to review your application for consistency with codes and regulations.



Planning Application Review

Flat rate. See application for amount.

Building Plan Review

Review fees vary from other Departments 

and Divisions.

Building Permit Fees

Includes fees for inspection, development 

impact fees, and other miscellaneous fees, which 

are generally determined by valuation of the 

project. See the link below for ADU building 

permit fees.

Additional fees will be invoiced when you pick up your Building Permit. These fees are based on the valuation of your overall project and includes fees for inspections and development impacts, such as schools and parks. Per State law, if the ADU is equal to or less than 749 square feet, the development impact fees are waived.  Visit the link below for a cost comparison of ADU Building Permit fees based on various sizes of ADUs.

Step 4: Budget

Learn more about budgets and financial considerations for ADUs.