Test pits are one of the most common uses of hydro and air excavation. It is also commonly referred to as daylighting, locating, and sub-surface utility engineering (SUE). It is the process of digging a test hole in order to locate underground utilities of which the location is more or less unknown.

Slot trenching is a common use of hydro and air excavation. Pressurized water or air is used to cut thin, accurate trenches of various dimensions, typically 6 to 24 inches wide and up to 8 feet deep. This method is effective in locating utility lines when their location is unknown.

Trenching is a common method of hydro and air excavation, with various forms available including slot, perimeter, box, linear, cross and exploratory trenching. Each variation is specific to the scope of work.