If you’re thinking about building an ADU, chances are someone’s already warned you: “It’s not worth the cost.” Or “You’ll never get your money back.” Or “Your neighbors won’t like it.”
After completing 100+ detached ADU builds across San Diego County, we’ve heard many of the concerns.
And while we agree: ADUs aren’t for everyone… we’ve also seen how often the so-called “drawbacks” are based on outdated thinking, myths, or missing context.
Here’s what people tend to get wrong and how to think critically about the tradeoffs.
- “ADUs are too expensive.”
- “ADUs hurt resale value.”
- “ADU appraisal values are too low.”
- “It will increase your property taxes.”
- “You’ll regret losing your yard.”
- “Your neighbors won’t like it.”
- “ADUs detract from the main home. There will be no privacy.”
- “It’ll be a nightmare to permit and build.”
- “ADUs take too long.”
- “ADUs limit financing options.”
- “ADUs are not the right move for investors.”
- Final Thought
“ADUs are too expensive.”
The Concern: ADUs cost a lot to build, and many people worry they will not get that money back. Compared with a remodel or a rental property purchase, the upfront investment feels high relative to the return.
The Answer: Yes, ADUs are a significant investment. But so is adding onto your home, buying a rental property, or moving to accommodate a family member. You’re investing in something that adds long-term value to your property and likely delivers far more flexibility, income potential, or multigenerational benefit than a remodel or off-site rental would.
When we surveyed past clients who completed an ADU, 94% said their finished ADU met or exceeded their expectations in terms of value added to their life. Over 58% said it exceeded expectations.
The value often comes from what the alternative would cost. If a family member needed nearby housing, buying or renting locally would be far more expensive. If a homeowner wanted rental income in their neighborhood, an ADU is often the only viable path without relocating. “We couldn’t have bought anything else in this neighborhood for anywhere near what we spent, and now we have exactly what we need.” – Brad, Homeowner in Oceanside (see the project)
To understand if an ADU makes sense for your budget, read more about all-in ADU costs and how to assess if an ADU is a good value.
“ADUs hurt resale value.”
The Concern: Some data, especially older studies, show that properties with ADUs do not always appraise much higher than those without. This raises fears that an ADU will not add meaningful value when selling.
The Answer: Early ADU sales data was limited and did not reflect demand for detached ADUs. Today the market looks different.
But don’t just take our word for it… let’s nerd out on some data. The Federal Housing Finance Agency (FHFA) analyzed a decade of California home data (2013-2023) and found that properties with ADUs outperformed those without; properties with ADUs appreciated materially faster.
FHFA Findings: Properties With ADUs Appreciated 21% Faster
| No ADU | With ADU | ||
| Appraised Values | 2013 | $405,000 | $550,000 |
| 2023 | $715,000 | $1,064,000 | |
| Overall Growth (10 yrs) | +77% | +93% |
Source: Federal Housing Finance Agency, 2025 – Trends in Median Appraised Value for Properties With ADUs in California
Still, resale performance depends on the type of ADU, location on the lot, parking, privacy, and local rental conditions. An ADU designed well and placed thoughtfully usually broadens the buyer pool rather than narrowing it.
“ADU appraisal values are too low.”
The concern: Appraisals often undervalue new ADUs compared to what they cost to build. This creates a negative initial equity position that can take years to recover.
The answer: It is true that ADU appraisals sometimes trail actual construction cost. That is not because the units lack value; it’s because appraisers are required to use recent comparable sales, and in many markets there still are not enough detached ADU comps to reflect real demand. ADU conversions also get blended into the same pool, which creates noise in the data.
As ADUs have become more common in San Diego, appraised values have improved. Lenders are issuing more ADU specific guidelines, and the recent FHFA data shows properties with ADUs appreciated materially faster over the past decade. Even with this progress, an appraisal will rarely capture the full benefit you are buying.
For many homeowners, the return is not driven by appraisal value. It is the ability to house family, secure long term stability, age in place, or create rental income in a location where buying another property is out of reach. For those who need immediate equity creation, an ADU is probably not the right vehicle. An ADU is a long term improvement to a property you already own, not a rapid equity extraction strategy.
Read more about what homeowners say is the biggest impact of having an ADU on their property.
“It will increase your property taxes.”
The Concern: Adding an ADU triggers reassessment on the improvement, which increases annual property taxes.
The Answer: Only the ADU is reassessed, not the main home. In San Diego County, taxes are roughly 1 percent of assessed value. Most ADUs are assessed using a discounted construction cost approach. A typical 1,000 square foot ADU might add about $1,650 a year in taxes. For many homeowners, rental income or improved property function more than offset that increase.
Read more about how ADUs affect property taxes.
“You’ll regret losing your yard.”
The Concern: Building an ADU reduces outdoor space and may make the property feel cramped.
The Answer: Backyards often go unused, and well designed ADUs can create more intentional outdoor living. Many homeowners add patios, courtyards, or shared-use spaces that improve flow. It is important to evaluate yard function early in design.
With thoughtful placement, fencing, and landscaping, owners often find the property feels more organized, not less.
Many homeowners reconfigure outdoor space to make it more functional. Here is one of our favorite examples in San Diego:
“Your neighbors won’t like it.”
The Concern: Neighbors may be worried about noise, renters, or construction disruption. HOAs may push back.
The Answer: ADUs are legal statewide and supported by cities as gentle density. Good design goes a long way toward reducing neighbor concerns. Keeping neighbors informed, respecting boundaries, and matching architectural elements usually results in positive outcomes. See how we design ADU exteriors to look intentional.
Even in HOA communities, state law is clear: homeowners associations cannot prohibit you from building an ADU. They can enforce reasonable design standards, but they can’t say “no” outright. In most cases, that means aligning finishes or rooflines, not blocking the project altogether.
Respect your neighbors? Always. But don’t let discomfort with their opinions – or outdated HOA rules – keep you from building something that adds lasting value and flexibility to your property.
“ADUs detract from the main home. There will be no privacy.”
The Concern: Some homeowners fear that adding an ADU will diminish the appeal of the main home. They worry the property will feel chopped up, less private, or harder to rent or sell because it becomes “two smaller living spaces” instead of one large single family home on a spacious lot.
The Answer: A well-designed ADU should feel like its own zone, not an encroachment. Privacy depends far more on thoughtful placement than on the size of the lot. Window orientations, door locations, fencing, and landscaping can create clear separation even on compact sites. A slight rotation of the footprint or shifting the ADU entry a few feet can eliminate sightlines entirely.
The concern about “splitting the lot” often assumes the market prefers one oversized single family home. That is not always true. In San Diego, many buyers and renters actually prefer two distinct living areas. Families want space for aging parents or young adults. House-hackers want a second income stream. Remote workers want a true separation between home and work. The flexibility created by an ADU often broadens the buyer and renter pool rather than shrinking it.
A large lot with a single structure offers limited utility. Meanwhile, a large lot with two purpose-built dwellings can support various uses, and utility is what many buyers prioritize today.
Dedicated access paths and strategic grading prevent the feeling of traffic through the main home’s domain. Trees, hedges, and screens establish a sense of territory that makes both spaces feel intentional and private. Many homeowners add flexible privacy solutions depending on how the ADU will be used. Removeable fencing or screens can offer complete separation when the unit is rented and be opened up when family stays in the ADU.
“It’ll be a nightmare to permit and build.”
The Concern: Permitting can drag on for months, and building a new structure feels overwhelming.
The Answer: Permitting is complex, but manageable with the right team. ADUs follow a defined process, and experienced firms know how to anticipate site conditions, fire requirements, utility needs, and agency reviews. The key is working with a team that:
- Understands state & local ADU regulations
- Has systems in place to manage plan check reviews and revisions
- Provides site-savvy feasibility analysis before design begins
Most homeowners who try to DIY this process entirely get overwhelmed. A design-build partner can take the complexity off your plate, or opt for a “Shell ADU” where the professionals take the build through drywall and you finish the interior with your own contractors.
Read about how SnapADU manages the entire process in-house.
“ADUs take too long.”
The Concern: Construction takes months, and there is no rental income until the project is complete.
The Answer: A detached ADU is not a quick project, but overall design-permit-build timelines can be close to a year with good planning. Key to shorter timelines:
- Start with a clear feasibility plan before diving into full design
- Consider a pre-approved or semi-custom plan
- Select a company that has deep experience in ADUs and will foresee & avoid roadblocks (read more about how to compare ADU companies)
If your priority is immediate rental yield, buying an existing property would start cash flow sooner. If your priority is housing a family member, securing control over your lot, or creating long term rental stability, the extra time is often worth it.
Owners who value predictability over speed tend to be the happiest ADU clients.
Read more about typical ADU timelines and what can speed up the process.
“ADUs limit financing options.”
The concern: Adding an ADU complicates financing and can push a property out of conventional loan categories, especially when multiple units are added.
The answer: Financing for ADUs is improving, but it is still more limited than financing for purchasing a stand-alone investment property. HELOCs and cash out refinances are the most common, and they can feel more expensive than DSCR or investment loans. That said, ADUs are also more accessible, have lower closing friction, and preserve the primary mortgage.
When multiple ADUs are added – and especially when the total units on the property exceeds 4 – conventional lenders will reclassify the property, which affects exit strategies. Buyers relying on conventional financing may face more limitations. This is important for investors who plan to sell quickly or structure a refinance play.
For homeowners building a single detached ADU, financing constraints are usually manageable. Options include HELOCs, cash out refis, construction-to-perm loans, and new ADU-specific loan products from regional banks. The financing picture is most challenging for investors expecting the property to behave like a small multifamily. ADUs do not convert a home into duplex zoning, and they do not unlock the same lending rules.
If maintaining broad exit flexibility is critical, you should understand how your lender classifies the property once the ADU is complete. If you are a long-term owner planning to hold, the financing structure is often a smaller factor compared to the stability and utility the ADU adds.
“ADUs are not the right move for investors.”
The concern: Investors can often get better returns buying another property. BRRRR projects (Buy, Rehab, Rent, Refinance, and Repeat) can create instant equity, while ADUs require significant capital and long lead times without immediate yield.
The answer: This is correct if the goal is short term forced appreciation. ADUs are not designed to beat a BRRRR on velocity; they are built on your existing land, which eliminates acquisition friction and long-term holding risk, but they do not deliver instant refinance value.
Where ADUs shine is in long-horizon scenarios.
Owners who want dependable rental income, multigenerational flexibility, or eventual downsizing often find the return profile more attractive than buying a second property in a competitive market. The all-in cost of an ADU is high, but so is the cost of acquiring another home with similar privacy, school district, and neighborhood controls.
The opportunity cost question cuts both ways. Yes, you could buy another rental and earn yield immediately. But many owners do not want to carry another large mortgage, take on a distant tenant, or compete for older homes that need upgrades. An ADU gives you a new unit that meets today’s code, energy efficiency, and layout expectations. It adds stable income or family utility without the volatility of a second property.
If you are an investor who prioritizes immediate leverage, rapid refinancing, or multifamily expansion potential, an ADU will not meet your expectations. If you are an owner focused on long term yield and flexibility, the economics look very different.
Final Thought
Building an ADU is a big decision, and yes, there are tradeoffs. Also, people worry about making an expensive mistake.
ADUs are not right for every scenario. They work best for homeowners who want long term flexibility, rental stability, or a way to house family members nearby. They are less ideal for flippers or investors seeking quick equity or rapid refinance potential.
The key is clarity. When owners understand their goals, the design and investment decisions become much easier.
The happiest clients we’ve worked with got clear on what mattered most and moved forward with confidence.
We are here to provide straightforward guidance and help you determine whether an ADU advances your priorities, both financially and personally. Contact us to get real answers.
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