Irlbeck says that in NRS’s experience, brackish groundwater desalination can be done for anywhere from $1 to $3 per thousand gallons, while seawater desalination can be anywhere from $3 to $6 per thousand gallons depending on the size of the facility.

As far as the actual cost of building a plant, that depends on a suite of factors. For instance, the KBH plant cost $87 million to build in 2007, the Texas Water Development Board noted, adding that “the 2010 biennial report on seawater desalination projected that it will cost approximately $32 million to build a 2.5 [million gallon per day] seawater desalination plant, and approximately $658 million to build a 100 [million gallon per day] seawater desalination plant in Texas.”

One possible solution is a growing movement within the U.S. water industry to turn to private financing of public infrastructure – the kind already seen in transportation with tollways and energy with private wind/solar farms, Irlbeck says.

“If you look at the infrastructure needed, the State Water Plan, there’s $56 billion of investment needed for that plan, and everyone’s fairly confident it’s not going to come from the state or federal or local budgets. So private sector financing of this public water infrastructure is going to be needed – and you’re starting to see cities solicit procurement for just that,” he says. “The City of San Antonio has a private water supply solicitation that’s came out in January 2011. […] I think by combining desalination technology and private financing there are going to be a lot of changes in the water sector moving forward.”

And as water prices continue to rise as a result of tightening supplies and greater demand, the “the price of desal will be less prohibitive,” Patterson says.

Irlbeck adds, “there are several emerging technologies that will eventually probably replace reverse osmosis as the preferred installed desalination technology. Right now reverse osmosis is what’s being installed – it’s a good, reliable off-the-shelf technology with good performance. But there’s a lot of research and development into that next generation of reverse osmosis and even different types of membranes.”

In the end, the United States really doesn’t have a water supply problem – the problem is with water quality, Irlbeck says. “We have a lot of water in the U.S., just not all of it’s fresh. In fact, the majority of it is not fresh. So as we start developing the limits of what is fresh, then we’re going to start figuring out how to cost-effectively treat that water that’s not fresh and begin using it.”