An electrodischarge apparatus has a nozzle that includes a discharge chamber that has an inlet for receiving water and an outlet. The apparatus has a first electrode extending into the discharge chamber that is electrically connected to one or more high-voltage capacitors. A second electrode is proximate to the first electrode to define a gap between the first and second electrodes. A switch causes the one or more capacitors to discharge across the gap between the electrodes to create a plasma bubble which expands to form a shockwave that escapes from the nozzle ahead of the plasma bubble.