In 1984, each New Yorker used 207.2 gallons of water per day; in 1996, 177.2 gallons per day; in 2006, 133.5 gallons. The reason? Tougher environment and building codes that require lower-flow showers, faucets, and low-water usage toilets. (The city has also redoubled its efforts to plug leaks in its vast water system.)

Investors may ask, why is the above important to know? Well, the national trend, and the trend for much of the world, for that matter, is toward more water-efficient and energy-efficient showers, clothes washers, dish washers, fixtures, toilets, appliances, etc., along with building codes that support that.

By extension, companies who make showers, clothes washers, dish washers, toilets, and appliances that are efficient or have a high energy saver rating are likely to be well-positioned. Think in these terms: imagine you're the toilet manufacturer that produces the most efficient, durable toilet for apartments and condos in New York City? Imagine what that could mean to that company's bottom line? And if the design is duplicated in other major U.S. cities.

Further, given the increased pressure on resources stemming from the development of emerging markets, there's little to suggest that water or energy will become less valuable in the decade ahead. In a very real sense, the future belongs to those companies that design products that use resources more efficiently, and in the weeks ahead, I'll profile a few.

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Financial Editor Joseph Lazzaro is based in New York.