Desalinating seawater sounds easy…

Better options: Conservation, reuse, storage and trading

In most places, several other supply options can and should be pursued in tandem before ocean desalination. All of these steps will provide more water at a lower cost.

The first and relatively cheapest way to address water shortages is by using less. Finding ways to get people to use less water could reduce existing demand by 30%-50% in many urban areas that have already begun conservation efforts.

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Second, recycling or reusing treated wastewater is often less expensive than desalination. Technology and regulations in this area are advancing, and this is already making large investments in recycling possible in many arid regions.

Third, storage capacity for enhanced capture of stormwater – even in areas where it rains infrequently – can be doubled or quadrupled in regions like Los Angeles and parts of Australia, at one-third to one-half of the cost per unit of desalinated water.

Even cleaning up polluted local groundwater supplies and purchasing water from nearby agricultural users, although these are costly and politically difficult strategies, may be prudent to consider before ocean desalination.