Experiments were done to photograph the structures of high pressure water jets, both continuous and pulsed, and to measure their surface erosion ability using mass-loss performance tests. Continuous and pulsed water jet was photographed to determine the effect of operating parameters such as nozzle diameter and pump pressure on jet velocity and discharge coefficient. For pulsed water jet the amplitude of the vibrating probe, and the position of the probe, were also varied. The rate of mass erosion of plastic samples exposed to water jets was measured. Zeolite powders, which were abrasive, were added to the pulsed water jet and found to increase the paint removal rate.