and seepage to the oceans. Groundwater storage can be much larger (in volume) compared to its inputs than surface water and have a slower turnover rate, though this depends on the features of the aquifer. This difference makes it easy for humans to use groundwater unsustainably for a long time without severe consequences. Nevertheless, over the long term the average rate of infiltration above a groundwater source plus input from streams is the upper bound for average consumption of water from that source.

Groundwater is naturally replenished