Are ADU's in Lafayette Worth It?

ADU’s, or accessory dwelling units, are becoming more common in Lafayette as affordability continues to be a challenge. Prior to 2023, the City only allowed ADU’s in the Old Town residential district. They passed additional measures that permitted homeowners to build ADU’s on their property and minimized the parking requirements and design standards, making the option more feasible for more owners.

What Counts as an ADU in Lafayette

An ADU is an independent living space on the same lot as a primary residence. Often called backyard cottages, casitas, or in-law suites, the popularity of ADU’s has grown significantly in recent years. As of 2025, the City of Lafayette allows ADU’s in most zoning districts that permit single-family homes. A detached ADU can be up to 750 square feet, up to 20 feet tall in Old Town and 16 feet tall in other residential areas, and must be located at least 10 feet from the front line of the main house and 5 feet from the rear property line. An attached ADU must match the size and design of the primary home. All ADU’s must go through the planning and permitting process with the City.

Bill HB24-1152 states that Lafayette can longer enforce parking requirements or require owner occupancy. HOA’s cannot prevent ADU’s outright but there are still reasonable design standards that can be enforced.

The Case for Building an ADU

An ADU provides additional square footage and potential income without needing to purchase a larger home. For current homeowners and sellers that is done a few ways.

Multigenerational living is one of the first reasons and ADU can be beneficial. Aging parents or adult kids can now have their own separate space without adding in an additional mortgage.

The income potential from having an ADU is also lucrative. Whether you decide to rent it out short-term or find a long-term renter, the additional income generated from the space can often offset overall mortgage costs.

Resale value is another benefit. Appraisers and buyers factor in a well-built ADU as both livable space and potential additional income, thereby increasing the overall value of the entire property.

Finally, there is flexibility. The space can evolve from a home office to a rental and then house family members in the future. The options can fit the homeowners current needs as the years pass.

The Case for Waiting

ADU’s are an expense and involve a potentially lengthier process that some homeowners may determine is not worthwhile.

Cost is typically the biggest reason for waiting. ADU’s can add up to be an expensive investment when factoring in the site work, utilities and permitting plus financing. A home equity line of credit, construction loan or cash out refinance are high cost factors to consider.

Timing is another reason that waiting may be the best option. Permitting and design standards, setback compliance and HOA regulations can set the project back by many months. If you don’t have the time and patience to invest, an ADU may not be the right choice.

Landlord responsibilities can be overwhelming to homeowners. Screening potential tenants, maintenance and local rental rules all run the risk of being something that is initially overlooked.

The Bottom Line for Lafayette Homeowners

The decision to build an ADU all comes down to numbers. What will be the total cost to build, how much would you charge or save and how long do you plan to be in the home. The ADU could eventually pay for itself with the right property and the right owner. But it could also be a drain on financial resources and personal bandwidth.

If you’re thinking of adding an ADU or looking to purchase a home that already has one, I am here to talk through what makes sense for your home goals.