For more than a decade, a battle has raged.  One one side we have Big Water, the corporations that have made bottled water a $46 billion a year industry, and on the other, what might be termed the Coalition of the Dripping, made up of the Earth’s resources, including water and petroleum (which is used to make, ship, and recycle water bottles), municipal services, and eco-warriors.

In 2001, Susan Wellington, then-president of the Quaker Oats Company’s United States beverage division, said, ”When we’re done, tap water will be relegated to showers and washing dishes.”

They’ve almost gotten away with it.  Big Water is astoundingly profitable — shocking considering that delicious, clean water flows readily from our taps, paid for by our taxes, proving that while you can’t sell ice to an Eskimo, you can melt it down, slap it with an exotic label, and sell it to the masses for $1.50 a pop.

But the tables are turning. Climate change has caught up with Big Water: Americans alone buy 28 billion water bottles a year and about 80% of those end up in landfills.  With the 1.5 million barrels of oil that are used to feed Americans’ thirst for disposable water bottles, we could fuel 100,000 cars a year.  Or we could not drink bottled water and not use that extra fuel in our cars, and prevent about 2.5 million tons of CO₂ from entering the atmosphere every year.

I recently signed the FilterForGood pledge, making a commitment to never buy a bottle of water again. Not everyone who signs the pledge need promise such an extreme change.  The point is to significantly reduce your current consumption.  To date, pledges have saved an estimated 99.5 million bottles.

My water bottle wastage wasn’t sky-high, but it was bad enough.  I used to buy about one bottle of water a week, and justified it by refilling it with tap water until it got too beaten-up and I abandoned it in some recycling bin or — gasp! — a garbage can.  But not only does this put undue stress on the environment, it put me in danger of exposure to BPA, a toxin found in plastic water bottles that is associated with Alzheimer’s, schizophrenia and depression.

As an avid (if lapsed) backpacker, I was psyched to learn that Nalgene, the maker of the classic, unbreakable water bottle, is now manufacturing BPA-free bottles, and is a partner in the FilterForGood campaign, along with BRITA, maker of water filters that reduce sediment and keep tap water conveniently cold in the fridge.

I invite you to join me in signing the pledge.  It’s one of the simplest ways to actively reduce your carbon footprint.  As campaign spokesman Josh Dorfman, author of The Lazy Environmentalist and CEO of Vivavi, a sustainable home furnishings company, told me:

What’s great about the pledge is that it asks people to consider how far their bottled water has traveled, and the size of its carbon footprint, but it doesn’t require a drastic change in behavior.  It’s in line with the ‘lazy environmentalist’ point of view.  People are already familiar with BRITA and adding reusable water bottle is a simple step to make a difference.  Financially, it’s in our self-interest.  The truth is, despite the talk that green has gone mainstream, that’s just not the case.  This is powerful because it’s environmental change that can be integrated into daily life.

And if you need it, here are five more reasons to never buy bottled water again:

1. In blind taste tests, drinkers can’t tell the difference between bottled and tap water.
2. Depending on the brand, bottled water costs 250 to 10,000 times tap water.
3. One study, conducted by The Archives of Family Medicine, found higher levels of baceteria in bottled water.
4. Tap water is strictly regulated and tested.  New York City’s water was tested 430,600 times during 2004 alone.
5. According to the United Nations World Health Organization, one billion people lack reliable access to potable water.  It is simply unethical that we are helping to destroy the planet for bottled water while clean drinking water drips down our drains — and one-sixth of the world is parched for a drop.