Soil has spaces between its particles. When water is poured over soil, then some of it gets absorbed in the soil and the rest passes down the soil. The process in which water passes down slowly through the soil is called percolation of water. Water can percolate through all types of soils. The percolation rats of water tells us how fast water passes down the soil. The percolation rate of water in a soil is the volume of water in milliliters (mL) which passes down the soil per minute.

Thus, percolation rate of water in a soil (mL/min)

$=\frac{Volumeofwaterpercolatedinsoil\left(inmL\right)}{Timetakenforthispercolation\left(in\min \right)}$