ADU Survey: Understanding Accessory Dwelling Units and Property Lines
California mandates that cities permit at least an 800 square foot accessory dwelling unit (ADU) on most residential lots, with no minimum lot size and setbacks as minimal as 4 feet from the side and rear property lines. Those specifications may seem straightforward until you're on your actual property. Where exactly is 4 feet from your property line, especially if the last survey of your lot was done decades ago or never occurred? That's where we come in.
What we provide includes:
- A topographic survey of existing grades, structures, walls, and utilities on your lot.
- Recorded property lines accurately resolved and plotted, ensuring your setbacks are measured from the true boundary, not an outdated fence.
- CAD (DWG) and PDF base maps specifically formatted for your city's ADU submittal.
- Property line staking before construction begins.
- Setback and height certifications during inspection.
- An as-built survey upon completion.
Why the property line matters more than many expect:
The 4-foot setback is a state minimum but only safeguards you if the line it’s measured from is accurate. We’ve encountered lots where existing fences, walls, or hedges are several feet away from the actual recorded boundary, sometimes affecting both neighbors. Constructing an ADU based on a fence line instead of the true property line can lead to misalignment, resulting in costly issues during inspection instead of before you start the groundwork.
A few important things to be aware of:
State law imposes no minimum lot size requirement for an ADU, meaning that small or uniquely shaped lots don’t automatically disqualify your plans. Garage conversions and same-footprint replacements typically are not subject to standard setback rules since the structure remains in its established position. Beyond the state's minimal requirements, your city may enforce its own height limits, design standards, and, particularly in coastal areas like Dana Point, a Coastal Development Permit requirement on top of the ADU approval itself.
Where this applies:
We specialize in ADU surveys throughout Orange County, including Dana Point, Laguna Beach, Laguna Niguel, San Clemente, and San Juan Capistrano. If your property is located in the Coastal Zone, we can inform you early about whether your ADU project will also require coastal permitting, ensuring you aren’t surprised later in the design process.
Call (949) 541-7004 or send us your site address.