Spoils

In hydrovac excavation, spoils consist of a mixture of soil, water, and any other materials encountered during digging, collectively forming a slurry. This slurry is vacuumed into the debris tank on the hydrovac truck and must be disposed of at an approved facility. Unlike dry excavation spoils, hydrovac slurry cannot typically be reused as backfill without dewatering.

Spoils disposal is a significant cost factor in hydrovac operations. The debris tank capacity determines how long a hydrovac truck can operate before it must leave the job site to dump. Tanks typically range from 6 to 15 cubic yards, and disposal sites may be located far from the work area, creating substantial non-productive travel time.

Contaminated spoils require special handling and disposal at licensed facilities. If the excavation occurs in an area with known or suspected soil contamination, the spoils must be tested and classified before disposal. Contaminated spoils disposal can cost significantly more than clean spoils disposal and may require hazardous waste manifesting and chain-of-custody documentation.