A group called Corporate Accountability International has been pressuring bottled water sellers to curb what it calls misleading marketing practices. The group has criticized PepsiCo over its blue Aquafina label with a mountain logo as perpetuating the misconception that the water comes from spring sources.

Aquafina is the single biggest bottled water brand, and its bottles are now labeled "P.W.S." The new labels will spell out "public water source."

"If this helps clarify the fact that the water originates from public sources, then it's a reasonable thing to do," PepsiCo spokeswoman Michelle Naughton said Friday. Aquafina water is taken from public sources then purified in a seven-step process.

The corporate accountability group is also pressing for similar concessions from The Coca-Cola Co., which owns the Dasani water brand, and Nestle Waters North America, seller of Nestle Pure Life purified drinking water, which gets some of its water from municipal sources.

Dasani's Web site says that Dasani comes from local water supplies, is filtered using a process called reverse osmosis and enhanced with minerals.

"We don't believe that consumers are confused about the source of Dasani water," Coca-Cola spokeswoman Diana Garza Ciarlante said. "The label clearly states that it is purified water."

Sales of bottled water has been a growing source of revenue for companies such as PepsiCo, based in Purchase, N.Y., and Atlanta-based Coca-Cola as they lessen their dependence on sales of traditional carbonated sodas, as consumer concern over health issues has weakened demand.

Nestle said Friday it has been printing new labels for its Pure Life water that say whether the water comes from municipal supplies or ground water, and the labels will begin showing up later this year. Pure Life is the only Nestle bottled water that uses public water sources and the company did not have an estimate for how much of its supply originates from public sources.