A salvage excavation is conducted at an endangered site or at sites that were already damaged during development work (paving, construction, etc.). A salvage excavation is the last chance for saving the archaeological and historical heritage of the site, and sometimes the site itself. Israel has seen rapid expansion and development in the last fifty years and many archaeological sites across the country have been disrupted and are still in danger. The Law of Antiquities entrusts the IAA, and its director, with the obligation and authority to protect these sites.

Preservation of the site begins in the planning stage, before infrastructure work is initiated. If the area is not well documented, a survey is necessary to identify archaeological remains. Based on the survey, the IAA may require a change in plans to shift the construction (roads, buildings, high-tension electric poles) away from the antiquities.

Antiquities are not always visible above surface, and in spite of careful planning, development works often expose archaeological remains. Antiquity inspectors are authorized to suspend work. Subsequently, the construction planners and archaeologists must consider ways to continue the work; a decision as to altering the plans or canceling the entire project needs to be reached.

If plans can not be changed or canceled (e.g., foundations for a bridge whose location depends on a specific road or streambed) a salvage excavation will be conducted. At its conclusion, another consultation is held in light of the remains from the excavation. If these are exceptional and significant, the IAA will oblige the contractor to alter his plans and preserve the remains beneath the new construction. This is a  radical and expensive solution for the developer, which is quite rare. In most cases, and depending on the character of the site, the IAA will permit work to continue, with the exception of the section destined for rebuilding, which will be completely excavated, documented and finds removed from the site, prior to its destruction.

Salvage excavations are also conducted at sites that were damaged by robbers in illegal excavations, as well as in ancient graves that were accidentally uncovered, and sometimes damaged.