Make it sustainable in pod form specifically. Pour over, drip, French/aeropress seem pretty sustainable. Especially of you use a mesh filter.

Many places actually do pump water uphill into reservoir lakes for hydroelectric dams. In that case it is a form of energy storage, a literal water battery.

Unfortunately, it’s not always a feasible option. For instance, in the great planes there’s not much of an uphill to pump the water to.