Is Water in Cans Greener Than Water in Bottles? No.

In fact, it might be worse for the environment.

LauriPatterson / Getty Images

There is a type of bottled water on the market, Ever & Ever, that comes in an aluminum can. It is not the only one. PepsiCo is also testing canned Aquafina water, evidently in response to environmental concerns. In recent years, public sentiment has turned against single-use plastic items, which can end up accumulating in landfills or floating in oceans. Across the world, only 9% of all the plastic ever made has been recycled; by contrast, 67% of the aluminum bought by consumers every year is reused.

Ever & Ever, in their marketing, extols the virtues of aluminum with some wonderfully creative copywriting: "Ever & Ever is a love letter to aluminum, the everlasting metal that has been around for approximately forever and will be around for approximately another forever, taking whatever shape humans require of it, silently, selflessly, without ego or waste, unlike plastic, which is a freeloader that's completely comfortable lying around in an ocean or landfill doing nothing."

The pitch that everyone is making is that an aluminum can is better for the environment than a PET (polyethylene terephthalate) bottle because aluminum is so easy to recycle. The problem is that it ain't necessarily so. Ever & Ever says "aluminum is infinitely recyclable" and "cans are made from an average of 70% recycled material."

But the problem is that other 30%. Even if recycling captured 100% of aluminum (it doesn't), there wouldn't be enough recycled material to meet demand because the market keeps growing and people keep thinking up new uses for it, like canned water. That means we need a lot of new aluminum.

Making primary aluminum is in almost every way an environmental disaster. First you have to mine the bauxite in Australia, Jamaica, Malaysia, and China, destroying agricultural lands and forests in the process. It's a sedimentary rock that is strip-mined in open-pit mines. Mining of bauxite ore has increased from 254 million metric tonnes in 2011 to nearly 390 million metric tonnes in 2021, thanks to increased demand, primarily from China.

Then you have to cook the bauxite in caustic soda and precipitate out the alumina hydrate. What's left behind is toxic "red mud" that recently caused a flood in Brazil when the dam holding it back failed, and earlier buried a town in Hungary.

Then you cook the alumina hydrate at 2000°C (3632°F) to drive off the water to get anhydrous alumina, or aluminum oxide, which is what you make aluminum from. Natural Resources Canada says, "It takes approximately 4 to 5 tonnes of bauxite ore to produce 2 tonnes of alumina. In turn, it takes approximately 2 tonnes of alumina to produce 1 tonne of aluminum."

Aluminum has been called "solid electricity" because it takes so much of it to separate the oxygen from the aluminum in alumina. That's why it often gets shipped off to Canada or Iceland where there is cheap, clean hydro power. But even there, they make it by sticking carbon anodes into pots so that when they jolt it with electricity, the carbon and oxygen combine to make, guess what, carbon dioxide.

So in the end, that 30% of new aluminum that goes into the can is just about the dirtiest material you can make—far worse than PET from a carbon and pollution point of view.

This is why we have to stop using aluminum for ephemeral things like single-use cans. In the book "Aluminum Upcycled", author Carl A. Zimrig explains that we have to reduce demand so that we don't need to make virgin aluminum:

And every time you buy an aluminum can, that is what you are doing, fueling environmental exploitation. British thinktank Green Alliance is quoted in Food Service Footprint after putting some numbers to it: "If half of the UK's plastic water bottles switched to cans, mining the aluminium could generate 162,010 tonnes of toxic waste, enough to fill up the Royal Albert Hall over six times."

Two other less important but still significant points:

As I noted earlier, quoting Carl Zimrig, aluminum is relatively easy to recycle and reuse, but it is not as clean and easy as people think. There are alloys that have to be removed using chemicals like chlorine; there are fumes and chemical releases that are toxic. "Although the contaminants released by recycling pale compared to the ecological damage of mining and smelting primary aluminum, the waste products of scrap recycling must be considered when considering the consequences of returning the metal to production."

Aluminum is not "infinitely recyclable" and cannot be turned into anything; according to the Wall Street Journal, it's not actually good enough for many uses. "Old cans are less versatile than other scrap. The makers of airplane and car parts prefer not to use aluminum made from recycled cans." So the refiners aren't bothering to recycle it since they get less money for it, and there isn't enough can sheet for the can makers, so these aluminum cans are often made from imported can sheet. Trump put a tariff on imported aluminum from China, so guess where it's coming from? As I wrote earlier:

In the end, you cannot say that an aluminum can is greener than a plastic bottle. It is true that it won't end up floating in the ocean, but that is the only good thing you can say about it. As the Green Alliance concluded, "Refilling reusable water bottles is the only sustainable alternative to single-use plastic."

Finally, there is the question of whether there is a BPA lining in the can, because bisphenol A is a possible endocrine disruptor. I asked Ever & Ever and they responded promptly:

The Ever & Ever people also make the case that you can reuse their screw-top bottle; they even recommend giving it an affectionate name like Samantha or Jake. They get points for that, and for their copywriting. I can even imagine people buying Ever & Ever because they can just pretend that they carry a reusable bottle; I always complain to my sustainable design students when they bring disposables to class, but what would I do with this?

In the end, nobody should think that an aluminum can full of water is actually better than a plastic bottle of water. I suspect that it is actually worse. The only truly sustainable way to drink water is from a reusable bottle, a glass, or from a drinking fountain. We have to use less aluminum and try to eliminate single-use aluminum products to "close the industrial loop." That's the reality.

Correction—April 1, 2022: This article has been corrected from a previous version which included an incorrect figure for bauxite mining.

"Bauxite Production Worldwide, from 2011 to 2020," Statista.

"Aluminum Facts," Natural Resources Canada.

"BPA," Environmental Working Group.