There are lots of myths and misunderstandings these days about water safety and health benefits. Is it dangerous to drink distilled water, even if it’s purer than tap water? And what’s with this alkaline water trend?

Let’s set the record straight here. Applying your knowledge of chemistry can help you cut through the marketing hype and fear mongering. The truth is often simpler than you might expect.

What Is Distilled Water?

Distilled water is simply water that has been purified through a process of distillation. That means it has been boiled, and the resulting steam has been collected and condensed, leaving you with what is, in theory, perfectly pure water (it is not a complicated set up, you could even do it at home).

Typical laboratory set-up for water distillation. Credit to Guruleninn via Wikipedia.

What does “perfectly pure” mean, in this case? Consider tap water, spring water, or any other water you might encounter in daily life. All of this water has some amount of other “stuff” in it besides hydrogen and oxygen.

Some of it might be stuff you can see, like algae in lake water, for example. But most of it will be invisible to the naked eye: dissolved minerals like calcium, sodium, potassium and magnesium, chlorides and bicarbonates, and sometimes additives like chlorine and fluoride in tap water in some regions.

There may even be microscopic critters swimming around in the water. Most of them are harmless, but some pathogenic microorganisms cause very serious illness (this is why so many cities treat their water supplies with a small amount of chlorine).

So, the perfectly pure water that comes from distillation is missing all of the above—it contains no minerals, no bacteria, no nothing. Just plain ol’ H 2 O.

Is it Safe to Drink?

The short answer is, yes, it’s safe to drink distilled water. But you might not want to make a habit of it.

Typically, distilled water of different qualities is employed to perform analytical chemistry techniques.

First of all, it’s not going to be any better for you than your regular tap water (assuming you are in an area where the water is safe to drink), and it can actually have certain negative long-term effects in some people.

Because it contains no minerals (i.e. electrolytes), it may be harder for your body to stay hydrated drinking distilled water, or you may get muscle cramps because of low calcium and magnesium. Still, these side effects are far from universal and certainly no reason to avoid distilled water if it is the only uncontaminated source available. You can always replenish electrolytes through food.

To illustrate just how safe it really is, consider that distilled water is often used to prepare formula for infants with particularly weak immune systems.

It has plenty of other uses, too. It’s essential for laboratory tests and chemical preparations like cosmetics, and it is very useful in cars and domestic appliances for reducing limescale and other mineral deposits.

But it’s not the best for drinking if you care at all about how your water tastes. If you look closely at any bottle of purified drinking water, you’ll see that, after purification, minerals have been added back into the water. This is because distilled water, without any minerals, tastes bland and flat.

Finally, it’s a lot more expensive than tap water. It’s worth paying extra to keep your car and clothes iron working smoothly, but for drinking? Why pay more for water that tastes bad and offers no benefits unless it’s really necessary?

What About Alkaline Water?

Speaking of water that is unnecessarily expensive and doesn’t offer any benefits…

I don’t know when this idea first came onto the scene, but I first heard someone peddling the idea of acidic and alkaline diets circa 2007. It didn’t seem terribly harmful at first—the proposed “alkaline diet” was rich in fresh vegetables and fruits, low in sugar and processed foods, and really an undeniably healthy way of eating—but this notion grabbed a foothold and is now being used to scam people out of their money with false health claims.

So now, over a decade later, alkaline water is being sold everywhere you look for exorbitant amounts of money compared to tap water. Depending on who you ask, this water will make sure your blood maintains its proper pH (very slightly basic), doing everything from reducing systemic inflammation to preventing cancer.

For anyone with a rudimentary understanding of chemistry and biochemistry, this is simply preposterous.

Yes, an alteration in your body’s pH is a big problem, but this does not happen as a result of consuming normal foods or drinks. We all eat and drink acidic and alkaline things every single day without any effect on the pH of our bodies. This is because the human body contains numerous regulatory mechanisms and buffering systems to prevent the things we ingest from affecting the pH of our blood or cells.

The body rids itself of excess acid by exhaling carbon dioxide, by excreting it through the kidneys, or by retaining bicarbonate.

Drinking alkaline water: safe but a waste of money

So, what happens if you do drink alkaline water? Think about where that water is going: straight into the highly acidic environment of your stomach. Your body has its own built-in water alkalinization system! Before it is absorbed by the colon, the acidic water from your stomach is neutralized by bicarbonate secretions from the pancreas.

Drinking Distilled Water: Water Quality

With all of this in mind, we can say that, in general, it is safe to drink distilled water. Most tap water, however, is equally safe to drink, tastes better and is much cheaper. But if you know that the area you are in does not have safe drinking water, you should not hesitate to drink distilled water if it is the only clean water available.

I guess the same could be said about alkaline water—if there’s nothing else safe to drink, by all means—but that’s the only good reason to do it. Put your chemistry knowledge to use, don’t be fooled by marketing gimmicks, and save your money.

If you want to impress a chemist with a gift, please, don’t even think about these kinds of scammy trends, there are so much better options!