‘Set‐down’ and set‐up, the negative and positive changes in mean water level due to the presence of a train of surface waves, was measured in a wave channel. Well outside the break point the experimental results are in good agreement with the theoretical relationship determined by Longuet‐Higgins and Stewart. Near the break point, where the wave height is greater than predicted by first‐order wave theory, the measured ‘set‐down’ was consistently less than theory would predict from the deep water wave height. Inside the break point the bore height was found to be a linear function of the mean water depth. In this region, the gradient of the set‐up, , was related to the beach slope tan β and the mean ratio of wave height to water depth by the equation .