For both new installation and rehabilitation work on underground utilities, it is necessary to understand various properties of the surrounding ground and environment. Many of these techniques would be part of any subsurface investigation. The emphasis here is on gathering information that it particularly important for trenchless installation or rehabilitation in utility work and that is gathered with little surface disturbance. Specific categories of information that are included in this chart are the types of soil/rock present (and their engineering and chemical properties), the electromagnetic environment present in the surrounding ground (including the presence of stray currents and the ground conductivity which can affect future corrosion potential), the thermal environment of the utility (e.g. the presence of nearby steam lines or the capability for heat loss from electrical transmission lines), and the groundwater environment (which can affect the planned construction or rehabilitation methods and their long-term performance).