Maybe it’s just the news we’re watching, but it does seem like carbon footprints, sustainable resourcing, and being eco-friendly are making their way into everyday life. And while, Wal-Mart and Marks & Spencer are making news this week, we’d like to see more attention paid to water footprints. Water is simply not fully accounted for in the same way carbon is.

For example, it takes water to generate energy. Lots of water. After agricultural use, power plants are the second largest water consumer in the country. Of course, not all of it is lost, as in the case of a hydro-power plant where the water continues downstream.

GreenBiz.com reported from last week’s Corporate Water Scarcity Risks and Footprints conference in San Francisco about the widely varying quantities of water needed to produce a kilowatt hour of electricity. Vice President of Engineering at CH2M Hill, Jan Dell, put it this way, “Not all electricity is water equal.”

Here’s how it breaks down according to the article:

• Coal uses 520 gallons of water to produce one megawatt for an hour.
• Carbon and capture coal needs 990 gallons of water for that same megawatt.
• A photovoltaic solar panel uses 30 gallons of water.
• Power from wind only requires one gallon per megawatt hour.

Most energy companies are not even tracking their water footprint but we expect that to change as climate change, pollution, and population continue to make greater demands on the planet’s 2.5 percent stash of fresh water.