10 April 2024
COMMON ADU QUESTIONS ANSWERED
By Professionals in the Field
ADU BASIC FACTS RELATED
1. What Is an Accessory Dwelling Unit (ADU)?
An accessory dwelling unit (ADU) is a small dwelling on the same premises as, or attached to, a single-family house. For example, it could be an unit over the garage, a basement unit, or a stand-alone house in the backyard. An ADU can be used to house a family member or for additional income through rent.
2. What are the Different Types of ADUs?
There are four main types of ADUs.
◈ New Attached ADUs – Shares a wall with the primary home.
◈ New Detached ADUs – Stand-alone units.
◈ Garage Conversion – Converting an existing garage.
◈ Internal ADUs – Constructed within the existing floor plan of a primary home. There are also basement and attic ADUs, that technically fall under internal ADUs.
3. What are JADUs?
A Junior ADU (JADU), is a secondary unit < 500 sq. ft. It is basically a smaller unit that can be built within the ‘envelope’ of an existing home. JADU has got few varying rules from that of an ADU:
◈ Can have a sharing bathroom with the main residence.
◈ Either JADU / Single-family residency (primary unit) must be owner-occupied.
◈ Has no parking requirements
◈ Must be attached to the primary residency.
◈ Needs an efficient kitchen.
4. What are advantages and disadvantages of JADUs?
Advantages: Can avoid various fees and have the option to share sanitation and utilities which makes it easier to build and more affordable.
Disadvantages: Must be < 500 sq.ft and should abide to owner occupancy regulations.
5. Where on property can the ADU be built?
The ADU must typically go in the backyard. It must be located at least 4 feet from the rear and side property lines (unless covering an existing garage). It can be fully Detached/attached to the main house/garage.
6. How Big Can an ADU Be?
◈ New 2023 ADU laws require all cities to have a height limit of min. 16 ft.
◈ If the property is within a ½ mile of public transit or already has a multi-family dwelling that is 2-storey high, the height limit must be min. 18 ft.
◈ If the ADU is attached to the primary dwelling, the height limit must be min. 25 ft or the zoning code of the property if that is lower. Cities can have higher height limitations than 16 feet, so where you live could be higher.
◈ A Detached ADUs can have a max. built up to 1,200 sq. ft. An Attached ADU, can be the lesser of 1200 sq. ft or 50% the size of the main unit. It can be either one or two stories.
◈ Consult your local planning board or an ADU professional to determine the ADU size limitation within your city.
7. What Are the Benefits of Building An ADU?
There are a multitude of benefits associated with building an ADU.
◈ Offers multi-generational housing opportunities.
◈ Income opportunity from renting the unit out.
◈ Helps the local community by offering affordable housing.
◈ House hacking opportunities
◈ Increases the value of your home.
◈ Provides extra living or non-living space.
ADU BASIC FACTS RELATED
ADU BASIC FACTS RELATED
1. What Is an Accessory Dwelling Unit (ADU)?
An accessory dwelling unit (ADU) is a small dwelling on the same premises as, or attached to, a single-family house. For example, it could be an unit over the garage, a basement unit, or a stand-alone house in the backyard. An ADU can be used to house a family member or for additional income through rent.
2. What are the Different Types of ADUs?
There are four main types of ADUs.
◈ New Attached ADUs – Shares a wall with the primary home.
◈ New Detached ADUs – Stand-alone units.
◈ Garage Conversion – Converting an existing garage.
◈ Internal ADUs – Constructed within the existing floor plan of primary home. There are also basement and attic ADUs, that technically fall under internal ADUs.
3. What are JADUs?
A Junior ADU (JADU), is a secondary unit < 500 sq. ft. It is basically a smaller unit that can be built within the ‘envelope’ of an existing home. JADU has got few varying rules from that of an ADU:
◈ Can have a sharing bathroom with the main residence.
◈ Either JADU / Single-family residency (primary unit) must be owner-occupied.
◈ Has no parking requirements
◈ Must be attached to the primary residency.
◈ Needs an efficiency kitchen.
4. What are advantages and disadvantages of JADUs?
Advantages: Can avoid various fees and have the option to share sanitation and utilities which makes it easier to build and more affordable.
Disadvantages: Must be < 500 sq.ft and should abide to owner occupancy regulations.
5. Where on property can the ADU be built?
The ADU must typically go in the backyard. It must be located at least 4 feet from the rear and side property lines (unless covering an existing garage). It can be fully Detached/attached to the main house / garage.
6. How Big Can an ADU Be?
◈ New 2023 ADU laws require all cities to have a height limit of min. 16 ft.
◈ If the property is within a ½ mile of public transit or already has a multi-family dwelling that is 2-storey high, the height limit must be min. 18 ft.
◈ If the ADU is attached to the primary dwelling, the height limit must be min. 25 ft or the zoning code of the property if that is lower. Cities can have higher height limitations than 16 feet, so where you live could be higher.
◈ A Detached ADUs can have a max. built up to 1,200 sq. ft. An Attached ADU, can be the lesser of 1200 sq. ft or 50% the size of the main unit. It can be either one or two stories.
◈ Consult your local planning board or an ADU professional to determine the ADU size limitation within your city.
7. What Are the Benefits of Building An ADU?
There are a multitude of benefits associated with building an ADU.
◈ Offers multi-generational housing opportunities.
◈ Income opportunity from renting the unit out.
◈ Helps the local community by offering affordable housing.
◈ House hacking opportunities
◈ Increases the value of your home.
◈ Provides extra living or non-living space.
ADU BASIC FACTS RELATED
8. How Much Does Building an ADU Cost?
Based on the ADU typology, location and the design taste the construction cost of an ADU shall vary. Depending on the ADU unit build, the prices can range from $80,000 to $300,000+.
◈ A 499 sq.ft new construction ADU can cost approx. $150,000 – $300,000.
◈ A 2-car garage conversion can cost approx. $70,000 – 120,000.
◈ Prefab: Depending on the make of the unit and the company you purchase it from; the prices can vary.
◈ Design and Local permit regulations incurring soft cost should also be considered in the ADU costing.
9. What are the City Fees Associated with ADUs?
◈ Plan check & permit fee for ADUs under 500 sq. ft : $3,000 – $5,000
◈ Plan check & permit fee for ADUs up to 749 sq. ft : $6,000 – $7,000
◈ Plan check & permit fee for ADUs over 750 sq. ft : $6,000 – $7,000 + Impact Fees (City shall add New development impact fees which will add thousands of dollars)
10. How Do I Finance An ADU?
There are a variety of local government grants and loans such as the CalHFA $40K ADU grant that can be utilize based on eligibility to fund the ADU project. Few other finance options are:
◈ Home Equity Loans and HELOCs
◈ Cash-out refinancing
◈ A personal line of credit
◈ Construction loan
◈ Renovation loan
◈ Chattel loan
◈ CDFI or local partnership loan program
◈ Peer-to-peer lending
◈ Cash savings
Its ideal to apply for grants and look at government programs, and then identify the best loan that will work for your financial situation.
11. Are There Ways to Save Costs on ADUs?
Few quick cost-saving tips to consider:
◈ Keeping your designs simple
◈ Use pre-approved floor plans to expedite the permitting process
◈ Buy customizable floor plans to save money on the design phase.
◈ Use affordable raw materials.
◈ Choose contractors who got established relationships with local raw material stores.
◈ Build a smaller unit.
◈ Consider doing a garage conversion if it is in good shape currently.
12. Does an ADU increase property tax?
Adding an ADU does increase your property tax, but it will not re-asses your existing house. That is, you’ll pay property taxes for your ADU for the present year while you continue paying the old property taxes for your main home. This is called a blended assessment.
13. What Is the Most Affordable ADU?
Usually Garage conversion is said to be the most affordable option for building an ADU yourself, since there is an existing structure, and probably may already have utilities and water hooked up to them.
Exception: However, if the garage foundation and structure are in bad shape, then it may cost more to fix them than to build an entirely new unit.
ADUs CONSTRUCTION RELATED
14. Best Way to Find an ADU Contractor?
To identify the best practitioner to execute your ADU project, make a checklist of qualifications you may want the contractor to have:
◈ Specialized in ADUs.
◈ Be licensed and insured.
◈ Have a network of subcontractors.
◈ Have good reviews.
◈ Be timely and responsive.
◈ Be familiar with local ADU laws.
◈ Have a supply chain plan.
15. How Do You Build An ADU?
Predominantly three ways of ADU construction:
i. Stick build construction: A contractor along with a team of subcontractors builds in the same way a traditional wood-frame home right on site.
ii. Modular (pre-fab) construction – Companies build the entire ADU in a factory and then assemble it on the property.
iii. Unique ADUs – Made of recycling shipping containers & other resources.
16. How Long Does It Take to Build An ADU?
Depending on the size and style of the build,
◈ A new construction ADU can take approx. 4 – 6 months depending on size.
◈ A garage conversion can take approx. 2 – 3 months depending on the condition the garage is in.
17. Can I Legalize an Unpermitted ADU or Garage Conversion?
To legalize an unpermitted ADU, you will have to bring it up to code and go through a series of inspections. Make a note, various states and cities have developed unit legalization programs to make this process easier. Suggest consulting the local planning board/ADU professional to determine what needs to be done to legalize your unpermitted ADU.
ADUs AND THEIR USES RELATED
18. Can ADUs Generate Rental Income?
ADUs can generate passive income by renting out the unit. However, one needs to be aware of the ADU rent control factors in respective city prior letting it for rental.
19. Do ADUs Help the Housing Crisis?
ADUs offer affordable housing options to low-income individuals, helping from becoming homeless. Therefore, many states like California have updated the laws to make ADU development easier for everyone in order to improve the housing crisis.
20. Do ADUs Make Good Retirement Homes?
ADUs serving as retirement homes is a great option to move your aging loved ones into your backyard so that can be assisted when they need help, yet they get to maintain a level of privacy and independence.
21. Does an ADU Make a Good Guest House?
ADUs make excellent guest houses if you often have company. Your guests can maintain a level of privacy while still being close to you. Using an ADU as a guest house is great for lodging traveling nurses, caretakers, or other personnel that often visit the home.
22. Can ADUs Be Used as Non-Living Space?
ADUs can be used for anything as long as it houses an efficient kitchen, bathroom, and living area. Few examples of how an ADU can be used:
◈ Art studio
◈ Home office
◈ Man cave
◈ Personal gym
◈ Personal movie theatre
◈ Pool house
◈ She shed.
◈ Yoga studio
23. Can ADUs Boost Property Value?
Depending on the property and its location, an ADU can improve the value of your home by 30%. ADU certainly help to boost the property value when you decide to sell in the future.
OTHER ADU QUESTIONS
24. Can You Sell an ADU Without the House?
An ADU cannot be bought or sold separately from the primary dwelling. Since it is on the same lot of land, it is considered a part of the primary dwelling’s property.
25. Can I Build an ADU And JADU?
You can build both an ADU and a JADU on your property. However, a JADU has an owner occupancy requirement that does not go away even if you already have an ADU on the property.
26. What Are Some of The Biggest ADU Mistakes?
Sharing a quick list of some of the biggest ADU mistakes you can make.
◈ Not comparing construction estimates
◈ Not creating a budget
◈ Not including laundry units
◈ Not planning for contingency when creating the budget
◈ Not planning for enough storage space
◈ Skipping ADU feasibility research
27. Do You Have ADU Appliance Recommendations?
When buying ADU appliances and furniture, also choose the options that have a dual purpose and save the most space. Here are a few options for you to consider.
◈ Refrigerator
◈ Range & microwave (or microwave/range hood combo)
◈ Dishwasher
◈ Ductless mini-split air conditioners and heaters
◈ Water heaters with Tank
◈ Workstation sink
◈ Washer and dryer combo
◈ Sectional sleeper sofa with storage compartments
28. Can My ADU Have a Separate Mailbox?
If you are renting out your ADU or using it for multi-generational housing, you probably don’t want your tenants’ mail getting mixed in with yours. Few of the cities, like Los Angeles, can issue you a separate address for your ADU.
29. Is There a Minimum Lot Size for Building An ADU?
There is no minimum lot size required for building an ADU. As long as the plot meets ADU zoning requirements and can allow for an ADU of at least 150 square feet to be built on it, it is good.
30. What Property Type Can I Build an ADU On?
Any residentially zoned property (single or multi-family) can have an ADU built on it, as long as there is an existing primary home on the lot.
31. Does building an ADU turn my property into a duplex?
Not officially because the zoning of your property doesn’t change. But for all intents and purposes, you will have a duplex-like property with two units you can rent.
32. Is Parking Required for ADUs?
If the unit is located within a 1/2 mile from public transit, no parking is required. However, if it is not, then probably you need to provide parking.
33. What Is the Best ADU To Build?
This depends on how you plan to use the ADU. Garage conversions tend to be the most affordable and less time-consuming. However, detached ADUs allow for more creativity in design. Attached JADUs are great for multi-generational housing because you can access them from your home without having to go outside. Therefore, the best ADU to build is different for everyone. A rental unit, with more bedrooms, equates into higher rent. Weigh the pros and cons of each type with an ADU professional before deciding what will be right for your needs.
34. Will ADUs require to have Fire sprinklers?
Construction of an ADU will not require fire sprinklers to be added to any existing primary dwelling.
35. What are the next steps after an ADU application is rejected?
When an ADU / JADU application is denied, a full list of items with descriptions of how the application can be fixed is required to be given. The applicant then can fix the items within a 60-day timeframe to act on the permit application.
36. Can My ADU Tap into Existing Utility Lines?
Since ADUs are generally stand-alone buildings, it will most likely require its own utility meters. However, some localities allow ADUs to tap into existing utility services on your property such as gas or water lines. View the respective City guidelines for ADUs.
37. Can we have separate utility meters for the ADU?
Yes, you can have separate meters for water and electric service but it will cost more to install. Instead ‘sub-meters’ shall be a lower-cost alternative.
38. Do ADUs require pedestrian access from the street?
Yes, a walking path access of 3’ wide is required from the front yard/sidewalk to the ADU (driveway is acceptable).
39. How much does an architect charge for ADU plans?
Depending on the size and complexity, full ADU plans should cost between $4,000-$12,000.
40. Are modular or pre-fab ADUs cheaper?
Not always. Although the price from the factory is often cheaper than from an ADU contractor, this price often may not include transportation or craning, and more importantly the foundation and utilities.
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