A critical step to developing an additional dwelling unit, otherwise known as an ADU, is developing a good floor plan. Creating one from scratch can be time-consuming and costly if you don’t know what you are doing. Luckily though, there are plenty of free ADU floor plan options for you to choose from for your project.
No matter what type of ADU you are building, there are pre-made ADU floor plans available for you to use. Read on to find a list of free and premium floor plans, where to find more, and what you need to do after choosing a floor plan.
Who Needs a Floor Plan?
Before we dive into various free floor plans for you to use, we need to define who needs a floor plan.
No matter what type of ADU you are constructing, you will need a floor plan. This includes:
- Attached ADUs
- Conversion ADUs
- Converting part of your home into an Internal ADU
- Detached ADUs
- Junior ADUs
- Turning a prebuilt modular into an ADU
An ADU floor plan is a key aspect of building an ADU. It is a crucial part of your permitting process and a major player in your design, build, and budget, no matter how big or small your project is.
Can Free Floor Plans Be Used for Permits?
Another important note for you to know before downloading an ADU floor plan is that it will need changes before you can submit it for permitting. These plans are the preliminary designs. Since every property is unique, the floor plan you download will need to be updated to match your specific site and the orientation of the ADU.
You will also need to check with your local planning department for a permitting checklist. You can often find one of these checklists online or by going into your local planning department with your starter plans and asking what else needs to be done. An ADU professional can also be of great assistance if you don’t want to take the time to figure it all out on your own.
Almost always, you will need the following items in addition to your floor plan to obtain your permits.
- Building elevations
- Building sections
- Electrical plan
- Foundation plan
- Framing plan
- Site/Plot plan
- Engineer calculations
- Energy calculations
Securing all these aspects can be difficult on your own. Hence, why we strongly recommend working with an ADU professional to save yourself time and the headache of figuring it all out.
Free San Diego County Floor Plans
The government of San Diego has made pre-designed, government-commissioned floor plans available to the public. They are free to use and include plans for several different unit sizes.
These floor plans are considered “county standard” floor plans. They meet all county laws and can be used as an additional resource for permit applicants to expedite the permitting process.
| Name | Size (SQFT) | Bedroom/Bathroom |
| Plan A | 1,200 | 3 Bedroom, 1 Bath |
| Plan D | 1,000 | 1 Bedroom, 1.5 Bath |
| Plan F | 600 | 1 Bedroom, 1 Bath |
For more San Diego County floor plans, please visit their County Standard ADU Building Plans page.
Free City of Encinitas Floor Plans
Many cities besides San Diego have made ADU floor plans available to the public. The catch for some of these cities though, is that they must be used within city limits.
For example, the city of Encinitas offers “permit ready” plans along with a checklist of what you need to do to get your ADU permitted. These plans include:
| Name | Size (SQFT) | Bedroom/Bathroom |
| Design Path Studios – Studio | 350 | Studio |
| Design Path Studios – 3BR, 3BA | 935 | 3 Bedroom, 3 Bath |
| DZN Partners – 2BR ,2BA | 990 | 2 Bedrooms, 2 Bath |
These plans must be used within the city of Encinitas. Make sure when you are looking at floor plans that they can be used in the city you live in.
For more permit-ready floor plans from the city of Encinitas, please see their Permit Ready ADU Program page.
Free Humboldt County Floor Plans
Humboldt County has commissioned floor plans for three different types of ADUs, as well as provided a summary of quick drawings and facts about each floor plan. Each of these plans requires correction to comply with the updated building code. However, they are a great starting point.
| Name | Size (SQFT) | Bedroom/Bathroom |
| Attached ADU | 660 | 1 Bedroom, 1 Bath |
| Detached ADU | 393 | 1 Bedroom, 1 Bath |
| Above Garage ADU | 517 | Studio |
For more information about what needs to be corrected for each plan, please see their Accessory Dwelling Unit Plans (Second Dwelling Units) page.
Free County of Placer Floor Plans
The County of Placer offers free county master plans for you to use as inspiration to save you time and money during the design phase. These plans will need to be updated like most free plans but are an excellent starting point.
| Name | Size (SQFT) | Bedroom/Bathroom |
| Black Oak & Cedar | 496 | 1 Bedroom, 1 Bath |
| Granite Plan A | 598 | 1 Bedroom, 1 Bath |
| Overlook & Tahoe | 749 | 1 Bedroom, 1 Bath |
This county offers an abundance of plans. To see their full list of floor plans, please go to their Free Accessory Home Plans page.
Free City of Stockton Floor Plans
The city of Stockton offers 3 pre-approved, free ADU floor plans that can be used within city limits. All plans utilize simple, cost-effective designs and meet the latest code requirements.
| Name | Size (SQFT) | Bedroom/Bathroom |
| Studio Floor Plan | 435 | Studio |
| 1 Bedroom Floor Plan | 625 | 1 Bedroom, 1 Bath |
| 2 Bedroom Floor Plan | 745 | 2 Bedroom, 1 Bath |
To learn more about building an ADU in Stockton, please click here.
Free City of Santa Cruz Floor Plans
The City of Santa Cruz offers inspiration for floor plans. Their offered designs are conceptual and still need more details to meet permitting requirements. However, they are a great base for you to start from to save you time and money as you design your ADU.
To see Santa Cruz’s conceptual floor plans, click here.
Should You Use Free Government Plans?
If you are going to use free plans, the best ones to use are going to be from the local government you are building within. Their free plans will meet most of their specifications, making it easier for you to get them through the permitting process.
The downfall to working with these plans is that they are not always updated when building codes are. Therefore, you need to be sure you bring your floor plan up to code before submitting it to be permitted.
Also, many of these plans can only be used in the city that created them. They cannot be used in other cities without tweaking the designs. Therefore, if you can’t find a free ADU plan for your city, it may make more sense to buy one or create your own.
Pre-Approved Floor Plans
Some cities offer pre-approved floor plans that can help expedite the permitting process. The City of Los Angeles and the City of San Jose both offer pre-approved plans. These plans are not all free though. However, they are a lot less costly than drawing up your own plans from scratch and are approved much quicker than other plans, saving you time and money.
Custom ADU Floor Plans
If your local government does not provide free floor plans and you did not find any that could transfer to your city that you like, there are other options. Many ADU professionals offer premium plans to fit your style and budget.
ADU Building Plans is a great example of a business that offers a wide selection of premium ADU floor plans to best fit your needs. To find the best plans for you, enter:
- Your property size
- The plan type you are looking for (design or construction)
- Your preferred style (contemporary, traditional, modern)
- How many stories your ADU will be
Plans can be customized to meet your needs and city’s specifications, making them easy to use in any county or city you are building within. Plus, saving you the time and money of having to design from scratch.
The great thing about ADU Building Plans is that besides ADU floor plans, they also offer:
- 3D design services
- 3D renderings
- Plan check revisions
- Site plans
- State/County/City general notes
- Structural engineering
- Title-24 energy calculations
Check out their ADU plans today to see if one meets your needs.
Start ADU Development Today!
Need help finding a floor plan that will work best for you or struggling to find your county’s ADU checklist? Let us help!
Here at Levi Design Build, we specialize in developing ADUs that save our customers time and money. Our personalized approach to every project guarantees your ADU will come out looking exactly how you want it. If you cannot find a floor plan that meets your needs, we can design one from scratch that stays within your budget and meets all building codes.
Contact us today for a free consultation to see how we can make your ADU dreams come to life!
