Looking for a new business trend?

Look no further than the water industry and water conservation, Susan J. Marks suggests.

Marks has just written the book Aqua Shock: The Water Crisis in America, and she's brimming with alarming facts and figures about the straits we're in and the solutions we're going to need so we don't run out of the precious liquid. "We use 408 billion gallons every day in the United States," she says. "Each of us uses 80 to 100 gallons for personal use each day. That's 152 tons of water per person per year."

Yes, the Earth is 70 percent water. But only 1 percent is the fresh water mankind needs to survive. "It's the new oil," she says. "There's a growing demand and a limited supply. But unlike oil, there's no alternative."

At least 36 states across the country expects water shortages of some kind by 2013, reports Marks, and 46 states are expected to be living under drought conditions by that time.

Shortages are caused by a variety of factors:

• Climate change
• Drought
• Population shifts to arid climates
• Overuse
• Worn-out sewer systems that leach precious freshwater supplies out of aquifers and carry it away as wastewater
• Outdated water-treatment plants that can't handle 21st century poisons
• Natural and man-made pollution
• Uncounted miles of pavement that keep water from soaking back into the ground to replenish our supplies.

"It's unfathomable that it can't be the great job generator," she adds. "Just factor in the 700,000 miles of pipe that have to be replaced underground.

"We often forget just how much water we use in this country. It's used for cooling, drilling and even creating electricity," Marks says. As she writes in Aqua Shock, "The United States has tapped into, sucked up and maxed out its once-abundant and replenishable supplies of freshwater on the surface and underground."

"Our infrastructure is crumbling," Marks says. "Try Googling 'water main break.' There are still pipes made out of brick and mortar. In Washington, there are pipes made out of wood. The big problem is not that they leak water," she says. "Instead, they pull fresh water out of the ground into the sewer system.

"Repairing infrastructure, saving water, using rain barrels to water your garden. All of this is ripe for entrepreneurship," Marks says.

New technologies are already coming into play. They include:

• Liners for pipes that are less expensive than complete pipe replacement
• Green roofs that absorb rainwater
• Pervious pavement, which allows rainwater to seep into the ground, rather than run off to the ocean.
• Dual-flush toilets that flush more or less water, depending on the amount of waste.
• Water-recycling pumps that send cold water from the hot water tap back to the hot water heater until the water heats up, rather than send the water down the drain.

And, of course, there are plenty of opportunities for lawyers, as cities, states and individuals square off in court over water rights and water use.

In Aqua Shock, Marks quotes Mike Hightower of Sandia National Laboratories: "Our efficiencies and new sources of water won't be from new rivers, new aquifers or any new freshwater sources. Instead, they will be from better management, better coordination, more efficient use of the water we already have, and additional use of nontraditional or alternative water resources like reusing wastewater or desalination."

Adds Marks, "What we need are innovation, technology and ingenuity to come up with new ideas."