Soft Dig

The term "soft dig" refers to any excavation method that avoids using hard, rigid equipment such as backhoe buckets, excavator teeth, or trencher chains in proximity to underground utilities. Hydrovac excavation and air excavation are the two primary soft dig methods used in the industry. Both use a pressurized medium (water or air) to loosen soil while a vacuum removes the spoils.

Soft dig methods are required by many utility owners and pipeline operators in their excavation specifications. The requirement is especially common when working within the tolerance zone of a marked utility, which is typically 18 to 24 inches on either side of the locate mark depending on state regulations. Within this zone, mechanical excavation is prohibited by law in many jurisdictions.

The cost of a soft dig is generally higher per cubic yard than mechanical excavation, but this is offset by the elimination of utility strike risk. A single utility strike can cost tens of thousands of dollars in repair costs, fines, and project delays, making soft dig methods the most cost-effective approach when working near buried infrastructure.