Is It Safe to Drink Deionized Water?

Why You Shouldn't Drink Deionized or DI Water

It's not healthy to drink deionized water or DI water for several reasons. Save it for labwork.
It's not healthy to drink deionized water or DI water for several reasons. Save it for the lab. Huntstock, Getty Images

It's usually okay to drink a small amount of deionized water, but there are several reasons why it would unsafe to drink a large volume of DI or to drink deionized water as your own form of water.

What Is Deionized Water?

Deionized water, abbreviated DI, is simply water from which the ions have been removed. Ordinary water contains many ions, such as Cu2+, Ca2+, and Mg2+. These ions most commonly are removed using an ion exchange process.

Deionized water may be used in laboratory situations where the presence of ions would cause interference or other problems. Important Note: Deionized water is not necessarily pure water. The purity depends on the composition of the source water. Deionizing does not remove pathogens or organic contaminants.

Reasons Why It's Not Safe To Drink Deionized Water

Aside from its unpleasant taste and sensation in your mouth, there are good reasons to avoid drinking deionized water:

  1. Deionized water lacks minerals normally found in water which have beneficial health effects. Calcium and magnesium, in particular, are desirable minerals in the water.
  2. Deionized water aggressively attacks pipes and storage container materials, leaching metals and other chemicals into the water.
  3. Drinking DI may lead to increased risk of metal toxicity, both because deionized water leaches metals from pipes and containers and because hard or mineral water protects against absorption of other metals by the body.
  1. Use of DI for cooking can lead to loss of minerals in food into the cooking water.
  2. At least one study found ingestion of deionized water directly damaged the intestinal mucosae. Other studies did not observe this effect.
  3. There is substantial evidence drinking DI disrupts mineral homeostasis. Longterm use of deionized water as drinking water may cause organ damage, even if additional minerals are present elsewhere in the diet.
  1. Distilled and DI water has been shown less able to quench thirst.
  2. Deionized water may contain contamination in the form of bits of ion exchange resin.
  3. While deionized water made from distilled or reverse osmosis purified water may be pure, deionizing nonpotable water will not make it safe to drink!

If You Simply Must Drink DI

I've tasted fresh deionized distilled water. It did not taste good and it felt sort of weird or prickly on my tongue. But, it did not dissolve my mouth like acid or anything like that. If I was locked in the lab storage room and had to choose between other solvents, DI, or heavy water, I'd drink the deionized water, but there are a couple of ways I'd make it safe:

  • Let the DI react with air. The water readily picks up ions from the atmosphere, quickly turning it into the ordinary purified water.
  • Don't let the deionized water run through pipes or glassware that has been encountered nasty chemicals. In other words, don't give the DI a chance to leach toxic metals or chemicals from its container.
  • Let the water settle and avoid drinking the portion at the bottom. Presumably, any ion exchange resin beads would sink to the bottom of the container. I do not know this for a fact, but I'd rather not drink them. An alternative would be to run the DI through a filter. Don't use a bleached coffee filter or paper towel, however, or you'll likely leach more dioxin into the water than remove potentially dangerous resin.

    Reference

    World Health Organization. Frantisek Kozisek. Health Risks from Drinking Demineralized Water. National Institute of Public Health, Czech Republic (retrieved September 16, 2015).