"Stop-work order issued. Encroachment onto adjacent property confirmed." That note landed on a Sacramento homeowner eight months into her prefab ADU build. The boundary survey she skipped would have cost $800. Correcting the encroachment cost $30,000, a full construction restart, and six months of silence with the neighbor next door. Property surveys are the least glamorous step in any ADU project -- and the most consequential one to skip. This post covers what builders get wrong, how to sequence the survey process to prevent disputes, and a checklist you can use before your permit application goes in. What Do Most Homeowners Get Wrong Before Building an ADU? Most disputes don't start with malice. They start with assumptions -- and the most expensive assumption is that the fence marks the legal boundary. Treating the Fence as a Property Line Fences are not legal property lines. They're where someone planted posts at some point, often without a survey. When you build...