Consumers will benefit from the decision by PepsiCo and Coca Cola, makers of the two bestselling brands of bottled water in the U.S. -- Aguafina and Dasani-- to identify both as being taken from municipal water supplies.

This is a positive step in public disclosure and in creating a public dialogue about the relative safety of tap water vesus bottled water, if indeed the revelations and the inquiry will be taken far enough.

Let's start with deceptive marketing. Yosemite water, for example, comes not from the Yosemite Valley, but from tap water taken from a street named Yosemite in the Highland Park neighborhood of Los Angeles. Crystal Geyer water comes from a well in Owens Valley, California, but the L.A. Department of Water also draws some of its tap water from this same source, only the municipality adds chlorine and fluoride to its supply.

By contrast, Calistoga Mineral Water comes direct from a capped geyser in Napa Valley and is accurately labeled "bottled at the source." We could go on and on identifying what water is and isn't from the actual source of a spring or glacier. But rigorous disclosure and truth in labeling will at least enable us to start making distinctions about the source of the water we consume.

My concerns with tap water go far beyond the fluoride and chlorine typically added by municipal water authorities. What never comes up in the news media is the extent to which many groundwater sources for municipal water supplies are contaminated by synthetic chemical pollutants that municipalities cannot test for, if only because they don't have the technology to do so even if they possessed the technology to remove the chemicals, which they don't.

As the U.S. Geological Survey has repeatedly reported, (discussed elsewhere on this blog page) every body of water in the U.S. --and in Europe-- that has been tested shows increasing levels of a wide range of chemicals from pharmaceutical drugs to endocrine disrupters and industrial agents. The Environmental Working Group organization has also begun to identify other synthetic chemicals in the wastewater that ends up being recycled as tap water. (see previous blog post.)

Reverse osmosis used by most municipalities on drinking water supplies may remove all or most organic contaminants, but these processes do not even begin to address the challenges posed by removal of synthetic chemicals that were designed to be virtually indestructible. (Reverse osmosis involves a separation process using pressure to force water through a membrane layer of polymers, which is the same process used to separate salt from sea water. Usually an activated carbon filter is used to trap organic chemicals.)

Aquafina, Dasani, and the other tap water brands claim to purify their supplies using this same reverse osmosis process. They then charge consumers much higher prices than if consumers simply filled their bottles up directly from the faucet. The Los Angeles Times calculated that a consumer can get 450 gallons of L.A. tap water for the price that same consumer would pay for 20 ounces of identical tap water being sold in plastic bottles.

According to the International Bottled Water Association, the average American drinks 27.6 gallons of bottled water a year. That means for every $5 spent on a container of bottled tap water, the same quantity can be drawn from the faucet for about half a penny. You do the math. It amounts to a huge ripoff, unless you believe convenience alone is worth the price. After all, who has a spigot on the dashboard of their car?

At least with bottled water that comes from glaciers or snow melt, and is accurately identified as such, we are paying for the fighting chance that the levels of synthetic chemical contaminants will be much lower than with municipal supplies.