The population of the world is growing at a rapid pace. Billions of people require more of just about every imaginable natural resource — oil, gas, grains, livestock, metals, materials and water.

Most people believe it will be difficult, if not impossible, for suppliers to meet the needs of businesses or consumers. And yet, a bump on China’s Great Wall… a small movement in the direction of restricting money supply… has caused adverse ripples in the stock prices of companies working along the resources stream.

As the global water supply becomes increasingly unbalanced, the case for “hydrocommerce” becomes more clear. Investors can access efforts to fix this dire situation with water-industry focused exchange traded funds.

The need for clean water is a pressing one. Based on recent surveys, groundwater levels, reservoirs, lakes and other forms of water capture and supply sources are running dangerously low around the world. Worse, investment in water infrastructure is nearly non-existent – the EPA estimates that the United States alone is $600 billion behind in water system upgrades.

The rise of the ETF industry has democratized commodity investing, making this asset class accessible to more investors than ever before. ETFs offer exposure, both direct and indirect, to almost every commodity imaginable, ranging from popular resources such as metals and grains to obscure commodities like adzuki beans and greasy wool. With all the attention paid to gold bullion and crude oil, investors often overlook one of the most important commodities: water.

Unlike most commodities, water has no real substitute, a fact that is raising concern as the world’s population expands more quickly than supplies of fresh, clean water. It is estimated that only 3% of all the water in the world is fresh and of that only 0.3% is above ground in lakes and rivers. With billions depending on the ability to make the most of this limited supply, the few unclaimed water supplies left are becoming increasingly valuable. As concerns about its scarcity in coming decades intensifies, water has the potential to become big business.