Fresh water comes from two places, either from ground water or surface water. Surface water include rivers, lakes, and ponds. Precipitation causes water runoff, where water is absorbed into the ground. Percolation is what causes the downward pull of water. Soil consists of porous matter, which is why water is able to be absorbed downward. Water eventually fills the lower level of soil composed of sand and gravel. The water table is formed above impermeable bedrock or clay. The more rain the larger the water table will be. As more and more water seeps downward a process called leaching happens. Leaching is when water that seeps downwards carries dissolved organic matter and minerals down to the lower levels of the soil.