SR-04Check for pipes and cables, and find your stopcockCables and pipes can run almost anywhere behind a bathroom wall, and a detector can miss cables that are deep, boxed in metal conduit, or behind old metal lath backing - always assume something is there until a small test hole proves otherwise. Before you drill, find your stopcock (usually under the kitchen sink) and check it turns freely, so you can shut the water off fast if you nick a pipe. If you have any real doubt about what's behind the wall, isolate the relevant circuit at the consumer unit before drilling and keep the stopcock in reach.