What are some common challenges when building a DADU?

Building a detached accessory dwelling unit (DADU) presents unique challenges, particularly during the planning and permitting phases. While attached ADU permits can be approved in a matter of weeks, DADU projects can take "two, three, even four months" due to more rigorous site and environmental reviews.

A primary challenge is dealing with site conditions. Erik notes that while many urban lots seem straightforward, there are often hidden issues. A significant problem he's encountered is when a homeowner believes their property is connected to the city sewer system, only to discover it's on a septic tank. Building on a septic drain field is typically not allowed and can completely derail a project.

"We've had those instances where we found out at the very beginning of planning that it was on a septic," he says.

Beyond unexpected septic systems, other challenges include ensuring proper drainage and navigating the complex regulations related to setbacks and lot coverage. Erik stresses that these are not just minor setbacks but major hurdles that can affect a project's viability. He advises that homeowners consult with their city or county, and work with experienced design-build firms or engineering teams to help identify and overcome these potential challenges early in the process.