Hydro excavation uses high pressure water to dig a hole! The high pressured water is used in conjunction with attachments as needed such as a jackhammer. The system uses a vacuum system to remove disturbed clay from site also.
This means that areas where there are high densities of utilities holes can be dug with less risk of striking and damaging underground cables, ideal for use in large urban areas. Reduced risk also reduces the potential costs from damaging utilities but also increases the safety of the operators.
One of the most common uses of hydro excavation is standing utility, sign or lighting poles where accompanied by a truck installed with manipulator crane it can be used without needing a digger on site.