What indicates a saturated soil condition?

• A. Soil is completely dry.
• B. All pore spaces in the soil are filled with water, and free water appears on the surface when the soil is manipulated.
• C. Only the top layer is wet.
• D. Pores are collapsed after compaction.

Answer: (B)

Saturation means every pore space in the soil is filled with water, with no air pockets left. In practice this shows up when the soil feels uniformly wet and, if you manipulate or squeeze it, free water exudes to the surface. That exudation of water demonstrates that water has filled all the voids and there’s no room for additional air-filled pores.

This differs from a completely dry soil, which has little to no water in the pores. If only the top layer is wet, deeper pores still contain air, so the soil isn’t saturated. Pores collapsing after compaction isn’t a sign of saturation; it indicates reduced porosity and altered structure, which affects water movement but doesn’t by itself prove all pores are filled with water.