Wholesale supplier Tampa Bay Water has begun selling water produced by the nation's largest reverse-osmosis seawater desalination facility. So far, the customers are public utilities in Florida's Hillsborough, Pasco, and Pinellas counties and the cities of New Port Richey, St. Petersburg, and Tampa.

At 25 mgd with the ability to expand production up to 35 mgd, the plant provides 10% of the water for 2.5 million residents in west-central Florida. A public-private partnership supported with $85 million from the Southwest Florida Water Management District, the plant is operated by American Water and Acciona Agua through a joint venture subsidiary called American Water-Pridesa.

The cost of the water is competitive with similarly sized plants around the world: $3.38/1,000 gallons.

As technological advances reduce the cost of desalinated water, Florida's new facility is the latest in a string of projects designed to open up new sources in drought-ridden areas of the country.

Last year, El Paso Water Utilities and the U.S. Army/Fort Bliss in Texas opened the largest inland desalination plant, a 27.5 mgd facility that's expected to increase drinking water production by 25% and supply the area with water for about 50 years. And California is spending more than $3 billion on a series of projects expected to supply 400 to 500 mgd of new drinking water by 2020 and provide up to 10% of the state's total water demand by 2030.