Which pores drain first after saturation?

• A. Micropores
• B. Mesopores
• C. All equally
• D. Macropores

Answer: (D)

Water drains from macropores first after saturation because their large openings let gravity pull the water out quickly and they experience much lower capillary suction. As these big pores empty, the remaining water is held by the smaller pores where capillary forces are stronger, so mesopores drain more slowly and micropores hold onto water the longest. In short, the largest pores give up water first, and the smallest pores retain it longer.