Since pre-Inca times, salt has been obtained in Maras by evaporating salty water from a local subterranean stream. The highly salty water emerges at a spring, a natural outlet of the underground stream. The flow is directed into an intricate system of tiny channels constructed so that the water runs gradually down onto the several hundred ancient terraced ponds. Almost all the ponds are less than four meters square in area, and none exceeds thirty centimeters in depth. All are necessarily shaped into polygons with the flow of water carefully controlled and monitored by the workers.

The owners of the salt ponds must be members of the community, and families that are new to the community wishing to propitiate a salt pond get the one farthest from the community. The size of the salt pond assigned to a family depends on the family's size. Usually there are many unused salt pools available to be farmed. Any prospective salt farmer need only locate an empty currently unmaintained pond, consult with the local informal cooperative, learn how to keep a pond properly within the accepted communal system, and start working.