Step 1 · Planning, Layout, and Permits
The first and most critical step is to create a detailed plan and obtain the necessary permits. Based on your finalized bathroom layout, draw a to-scale plumbing plan. This plan should show the exact location of the toilet, sink, and shower drains. Use a tape measure, framing square, and chalk line to transfer these locations onto the concrete floor. Mark the centerlines for each fixture's drain. For the toilet, the standard is 12 inches from the finished wall to the center of the drain. For the sink, it's the center of the vanity. For the shower, it's the center of the shower base. Research your local plumbing codes (e.g., IPC or UPC) to understand requirements for pipe sizing, drain slope (typically 1/4 inch per foot), and venting distances. Submit your plans to your local building department to secure a plumbing permit before any demolition begins.