1. To become dissolved, eroded, or carried away, by or as by some percolating liquid. Nutrients in the soil have continued leaching away as the groundwater become more acidic. The calcium in the sandstone leached away over time as water levels rose.
2. To dissolve, erode, or carry something away due to percolation. In this usage, a noun or pronoun can be used between "leach" and "away." Increasingly acidic water has been leaching away important minerals from the land. Over time, the saltwater leached the limestone away all along the coastline.
leach something away (from something)and leach something out (of something); leach something out; leach something away
to remove something from something by leaching. The heavy rains leached nutrients away from the soil. The rains leached away the nutrients.
[for something] to erode or wash away gradually by leaching. The soft sandstone leached away under the constant rains. The flowerpots sat out in the rain, where all the nutrients in the soil leached away.