Frequently Asked Questions


Accessory dwelling units (ADUs) are separate or attached housing units built on existing single or multifamily residential properties. ADUs are also known as second dwelling units, guest houses, casitas, backyard cottages, mother-in-law units, and granny flats. There are many different types of ADUs, including both separate structures located in a back or side yard (detached) and conversions of existing spaces such as basements, attics and garages (attached). For more information, we recommend Kol Peterson’s blog at

At Habitat, we offer only detached prefab ADUs. This keeps the process as simple and cost-effective as possible for you.

In 2020 and 2021, California passed a series of bills to make it easier for homeowners to build ADUs. Major changes to zoning regulations, permit requirements, and developmental standards supersede previously restrictive local regulations. While zoning, regulations, and fees vary by municipality, the recent state laws say that ADUs can be built on property zoned for single-family and multifamily use.

If you live on a residential lot with enough space, you can build one detached ADU and one junior ADU (a unit no bigger than 500 square feet located within the home). If you live on a multifamily lot, a maximum of two detached ADUs are allowed on the property.

Thousands of ADUs are being built in communities across the U.S. because they are a manageable and minimally disruptive option for adding needed housing to existing neighborhoods. Moreover, ADUs typically cost less than other forms of housing and make efficient use of existing land.

The other factor driving ADU building is that ADUs serve many needs that mirror socioeconomic trends in the U.S. They allow for people to age in place or form multigenerational households to ease caregiving responsibilities and cost. Given the high cost to buy a house, homeowners are frequently turning to ADUs to provide additional income to make ends meet. Also, the appeal of downsizing and minimalist living seems to be growing, and ADUs allow people to simplify their lives and still live in a neighborhood setting.

Our average build takes about six months from start to finish. Each project will vary depending on its location and scope of work.


Traditional on-site builds are costly, unpredictable, and take time to coordinate and sequence the work. Labor costs, unexpected construction hurdles and finicky local and state building codes can turn a building project into a nightmare. That’s why we specialize in prefabricated homes, an efficient and cost-effective approach to building in your backyard.


‘Prefab’ is shorthand for ‘Previously Fabricated’, meaning it was built in a factory and is reassembled or finished onsite. Our units are built to completion in our partner factories, transported to your site, and can be installed to a foundation within 48 hours. Prefab construction has the advantage of significantly faster and more efficient than other construction types. Building in a factory allows us to use efficient processes and avoid weather delays, so that we can complete your project on time and on schedule!

Many different types of properties will accommodate an ADU, and our floor plan options are flexible to fit your backyard. A member of our team can qualify your property online and let you know if we can build.

Our ADUs are built on a stem wall foundation.


Yes, the foundation will be engineered for earthquake safety and your local building/engineering department will be required to review and confirm.


ADUs access sewer and water service by connecting to the main sewer and water service to the primary residence. In most cases, a connection to the sewer is established outside the primary residence, and a connection to water service is accessed through the foundation into the basement of the primary residence. Our ADUs connect to existing electrical service through either the main panel or a separate panel on the outside of the house.


Our units are all electric to comply with CA state law and require 200 amps. We can help you update your electric panel if necessary!


We may need to upgrade your perk system to allow for more capacity. The upgrade will depend on the capacity of your existing system and the size of your unit selection.


Our units do come outfitted with a 15 kW electric furnace, which is rated to provide enough heat for a 1,500 sq. ft. of interior space. Our units do not come outfitted with A/C in the standard package, but we are able to offer A/C as an upgrade.


It depends. Cities often have special building regulations for hillside construction. Reach out to us, and we’ll determine if it’s a feasible project.


The manufactured home is constructed to comply with the preemptive National Manufactured Home Construction and Safety Standards, a uniform building standard administered and enforced by the U.S. Department of Housing and Urban Development (HUD Code), which supersedes all local building codes on the home itself. Manufactured Homes are NOT the same as Mobile homes. Mobile homes have not been constructed since June 15, 1976 at which time the federal preemptive HUD Code took effect. Manufactured homes placed on permanent foundations become part of the real estate and therefore as the surrounding area adjusts with the market, so will the manufactured and land package.


Manufactured Homes tend to have a more stringent Inspection/Enforcement process than stick built homes do. It can generally be acknowledged that a building code is only as good as the enforcement system that accompanies it. The manufactured home enforcement program required by the HUD is a thorough and efficient system designed specifically for the factory production environment. Uniformity and consistency can be maintained better in the HUD enforcement system because of two key factors. First, the inspections take place in the factory, during each phase of construction, and follow behind the manufacturer’s own in-plant inspection and quality assurance teams. This allows for more thoroughness, since time is spent inspecting homes rather than traveling to inspection sites. Efficiency is increased because travel time is limited and necessary paperwork is minimized. Second, consistency is maintained because fewer people inspect more homes. The enforcement procedure is much less susceptible to individual interpretations, as would be the case with on-site inspections in every jurisdiction across the country.


The benefits of the HUD CODE are numerous! The quality of construction has significantly improved. The HUD Code allows for a more lenient process for obtaining permits from your local building department. As a HUD approved home, the entire plan approval process is bypassed because a manufactured home has already been approved by a Federal Agency which supersedes any local jurisdiction. The federal standards regulate manufactured housing design and construction, strength and durability, transportability, fire resistance, energy efficiency and quality. The HUD Code also sets performance standards for the heating, plumbing, air conditioning, thermal and electrical systems. It is the only federally-regulated national building code. On-site additions, such as garages, decks and porches, often add to the attractiveness of manufactured homes and must be built to local, state or regional building codes.


Manufactured homes are built with the same materials as a stick-built homes, and endure a more stringent inspection process to assure a high-quality construction, which offers the same or more technological advances to improve the functionality, esthetics, and efficiencies of the home. The best part is that all of these benefits come at price up to 45 percent less per square foot than a newly constructed traditional site-built home.

Technological advances, evolutionary designs, and a focus on delivering quality homes that families can afford are the driving forces within the manufactured housing industry. That’s why more people are turning to manufactured housing to deliver homes that fit their needs and wants, at prices they can afford!

The affordability of manufactured housing can be attributed directly to the efficiencies emanating from the factory-building process. The controlled construction environment and assembly-line techniques remove many of the problems encountered during traditional home construction, such as poor weather, theft, vandalism, damage to building products and materials, and unskilled labor. Factory employees are trained and managed more effectively and efficiently than the system of contracted labor employed by the site-built home construction industry.

Much like other assembly-line operations, manufactured homes benefit from the economics of scale resulting from purchasing large quantities of materials, products and appliances. Manufactured home builders are able to negotiate substantial savings on many components used in building a home, with these savings passed on directly to the homebuyer.

There are also Green (earth friendly) Benefits that come from building a home in a factory environment. Prefabrication techniques reduce waste, offer energy-saving designs and improve manufacturing and construction efficiencies. Time savings is also an advantage with factory production. Manufactured Homes placed on private property will normally have a 3–6-month timeframe depending on the process. The main time benefits with manufactured homes are the pre-emptive HUD Code as well as being able to complete both construction on site and the home in the factory simultaneously. The HUD code allows for homes to be streamlined through plan check at the building department; these homes are federally approved which supersedes local building jurisdictions. This timeframe would include obtaining financing, permits, factory production time, and on-site completion.

Permitting & City Approval

The planning department must review your project in 60 days or less.


Very unlikely! According to state law, an additional parking spot is not needed if the ADU: is located within ½ mile of a public bus stop or rail station; is on a street that requires on-street parking permits, but the permit has not been offered to the occupant of the ADU; is located within one block of a public car-share program. In fact, if you demolish a parking stall in order to build an ADU, and your property is within ½ mile of a bus stop, you don’t have to replace the parking stall you demolished!


State law says that all ADU must be at least 4 feet from the rear and side yard, unless there are special circumstances with your property (i.e. on a grade). This is the case for all ADUs in California.


It will depend on your property and what project you have in mind. Most report requirements are void with the new ADU laws, but every property is going to be different. The good news is our management team will handle all required reports.


No! The new 2020 state regulations specifically prohibit HOAs from interfering with ADU construction.


We will establish separate cable and, if desired, phone service to the ADU. If the ADU is rented out, these bills can be assumed by the tenant. In most cases, the homeowner will add another garbage receptacle to their monthly bill and bill the tenant for the additional cost. Existing recycling receptacles should be sufficient for the ADUs’ recycling needs.


All permitted ADUs are assigned a separate mailing address usually by adding “A” to the primary residence and “B” to the ADU. When requested, we will install a separate mailbox in a location compatible with existing mail service.


Prices & financing

The primary home will not be reassessed – ADUs do not trigger Prop 13! Your property tax will be recalculated based on a “blended assessment.” This blended assessment will increase your annual property tax by roughly 1% of the value of the ADU.

A blended assessment means the base value of the existing house will stay the same. Your accessory dwelling unit’s additional value at the current market rate will be added to the existing home’s value. What happens to my depreciation schedule? We build one for you!

We are not a lending institution, but we can direct you to our ADU financing partners who will help you decide the best way to finance the project.

The Department of Justice promotes financial security for service members, recent veterans, and military family members through its Service members Civil Relief Act (“SCRA”), including caps for interest rates and mortgages.

Yes. ADUs can be rented out just like any other residence, including to Section 8 voucher holders. Learn more about Section 8 Housing Choice Voucher here.

Each payment schedule is tailored to your needs. Schedule a call with one of our ADU experts to discuss


We work to identify them in advance, and our units are specially tailored to reduce future unknowns.


The presence of an ADU can often enhance the attractiveness of a house on the market, and increasingly investments in new ADUs are being reflected in the appraised value of those properties.


Designing your unit

We have 10 standard floor plan options to choose from, and there are further options within those standard designs. For example, we can mirror the unit layout. 

Speak with a team member directly to hear about our managed customization options.

We offer a selection of curated design options as standard features, and upgrades are available. Certain features can be customized for material and color, such as siding, but most elements are available only in the selections we offer. This is so we can keep the process as simple and efficient as possible for you.

Our standard roof material is a black, 3-tab asphalt shingle. We cannot accommodate custom roof materials, but it is fairly easy to install another roof type on top of the existing composite shingle roof should you choose to do so.

Our standard flooring options include carpet and linoleum, with the option to upgrade to plank vinyl. While we do not provide wood flooring options at this time, we can ship the unit without flooring if you choose to install your own.

Our units ship with all of the appliances installed! Our units come with a Whirlpool slide-in electric range with oven, refrigerator, dishwasher, and microwave/range hood combination; the front-load washer and dryer are from LG. 

If you have appliances you would like to install, we can discuss during your design session. In order to receive a certificate of occupancy, the appliances will need to be installed first. If you do have your own appliances, if you can provide us the specs and we will work to ensure the right amount of space for them.

We cannot make a home officially compliant to ADA standards, but can work with you to install features to make the unit more accessible, such as wheelchair ramps. The cost depends on the specific features and scope of work.

Extra construction and landscaping projects are not within our standard scope of work. We can advise you on a general budget for additional site work, but we do not include it in our project proposal quotes.

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