An understanding of mechanical waves is a pre?requisite for the study of many topics in advanced physics, and indeed in many other disciplines. There have been many research studies in mechanical waves, all of which have revealed that students have trouble with the basic concepts. Therefore, in order for teachers to prepare appropriate instruction for their classes, it is useful to diagnose their students' conceptions--if possible before they enter class. It is for this purpose that many diagnostic instruments have been developed, often in the form of multiple?choice tests. In this study, we have used the open?ended Wave Diagnostic Test to develop a multiple?choice conceptual survey in an evolutionary manner. The two?year development procedure included open?ended surveys and interviews involving 299 Thai students and 88 Australian students. The final version, called the Mechanical Waves Conceptual Survey, has been administered to 632 Australian students from high school to second?year university and 270 Thai high school students. Standard statistical analyses show that the survey is reliable and valid. Further validity checks, including consultation with experts, were also carried out. The survey has four subtopics--propagation, superposition, reflection, and standing waves--and the teachers can choose the subtopics relevant for their students. In this paper we also demonstrate the use of a typical survey question to test students' conceptual understanding and identify common alternative conceptions.