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How Long Does Distilled Water Last [Find Out The Truth]

how long does distilled water lastTheoretically, distilled water should last longer than conventional bottled water because it is the cleanest water on earth. For the variety of usage, knowing the expiration of distilled water is essential.

So, how long does distilled water last? Distilled water can last almost indefinitely if you store it properly. It has a five-year shelf life if it is not opened. That is more than regular bottled water, which only lasts two.

We will talk about the longevity of distilled water so that you know when you should change it. We will also share tips to increase the expiration time of distilled water.

How Long Does Distilled Water Last?

Boiling, catching the steam, and putting it back in a liquid condition creates distilled water. All of the poisons, chemicals, and other pollutants are eliminated throughout this procedure.

As a result, this type of water is known to be purer than ordinary bottled water. Moreover, this procedure increases the water’s shelf life.

You may find a best-before date on distilled water bottles. However, they tend to last longer than this date. It is indefinite how long distilled water will last if you store them properly. However, they will certainly last for years. When unopened, this time will extend for another few years.

While distilled water might be contaminated, it is often not wasted. Both the packing procedure and environmental elements (such as air pollution) can have an impact on the purity of the water. Nowadays, people tend to use megahome water distillers or countertop water distillers for the best output.

Distilled water kept in a closed glass bottle will last longer than in a plastic container. Since plastic is biodegradable, pollutants will gradually seep into the water, lowering its purity. As a consequent, the quality of home-distilled water will probably remain at its peak for about a week.

After that, it could begin to smell a little stale. Although it remains safe to use and drink, it is better to throw it away.

Longevity Of Different Types of Distilled Water

The following table will give an overview of the longevity of the different types of distilled water,

Condition Longevity/ Time before the expiration
Distilled water that is  kept in a sealed bottle More than 5 years
Distilled water that is kept in an opened bottle for home appliance More than 1 year
Distilled water that is kept in an opened bottle for drinking 4 to 7 days
Home-distilled water 4 to 7 days

Is it Safe to Drink or Use Expired Distilled Water?

Often, humidifiers and CPAP (Continuous Positive Airway Pressure) machines rely on distilled water to operate. You can even use expired distilled water for both appliances though it is not suggested. You just need to make sure the water is not contaminated.

Remember, if distilled water in your humidifier is filled with mold or fungus, it will be bad for your lungs. Especially for CPAP machines, the chances of respiratory illness will rise if it is filled with contaminated distilled water. It can also lead to sleep apnea-hypopnea syndrome.

You may want to store distilled water for a while if you want to use it for home appliances. A container made of high-density polyethylene would be a great choice for this unless you simply need to hold a few ounces.

Speaking of drinking distilled water, it is safe to drink it, but not often. Yet you will probably discover it to be smooth or flat. That is because it eliminates crucial minerals like calcium, salt, and magnesium, which are responsible for tap water’s well-known flavor. Hydrogen and oxygen are the only elements left.

From EPA’s statement, we have found,

“High levels of chemical exposure can cause skin discoloration or even more serious issues including organ or nervous system damage.”

Smelling before tasting is the greatest approach to prevent consuming tainted distilled water. Also, look for particles or mold. Throw away your distilled water immediately if it tastes or smells weird.

Common Uses of Distilled Water

When purity is a top priority, distilled water is the best option. There are various uses of distilled water, both commercial and residential. Let’s look at the mentionable uses of distilled water,

How to Maximize Distilled Water Expiration?

If you apply some procedure, you can make distilled water last longer than usual. Although the following approaches are not suggested for drinking distilled water, they are good when preserving distilled water for home appliances.

Use a Reliable Container to Store Distilled Water

If you use a glass bottle to store distilled water for drinking, it will extend its life more than storing water in a plastic water bottle. However, a High-Density Polyethylene (HDPE) drum is better for storing distilled water in larger quantities.

Keep Distilled Water Containers Sealed

Distilled water becomes contaminant-prone the moment it is exposed to the air. Despite the fact that distilled water lacks nutrition, certain germs and bacteria can develop quickly if the container is not shut.

Keep Containers Away from Contaminants

Distilled water can acquire an unpleasant odor if it is kept next to chemicals with strong smells, such as paint or gasoline. As a result, water will likely have an odd flavor though it won’t necessarily be harmful to drink.

Refrigerate Open Distilled Bottles

As you already know, opening a container of distilled water will allow airborne contaminants to mix with it. One way to stop this is to preserve the container or bottle in a refrigerator. This will enhance the purity of water by preventing the growth of any bacteria or germs.

Place the Container Under Sunlight (Based on the Type)

This approach is dynamic. Meaning it can be good or bad depending on the type of container. If you use a plastic bottle, direct sunlight will cause the small plastic components to lose their integrity, allowing them to move freely inside the water.

In contrast, keeping distilled water in a glass bottle under the sun (about 5 to 48 hours) will purify it.


Here are a few things about distilled water if you are one of those concerned ones about distilled water.

Q1. Does distilled water allow bacteria to grow?

Yes, bacteria may eventually grow in distilled water whether you open the bottle or not. Various microorganisms can grow in this type of water. These include Caulobacter spp., Arthrobacter spp., Pseudomonas spp., Seliberia spp., Hyphomicrobium spp., Mycobacterium spp., Chlorella spp., and yeasts.

Q2. Does distilled water allow the fungus to grow?

Yes indeed. Mold or fungus may grow in distilled water after a certain period. These can not only grow but also live in distilled water because the majority of distillation techniques still permit the presence of trace elements and chemicals in the water.


So, how long does distilled water last? As we have explained earlier, they can last indefinitely if you store them correctly. They tend to last longer than ordinary bottled water.

Additionally, you know how you can increase the expiration time of distilled water. Just follow the tips that we have shared, and you will be able to store distilled water longer than usual. As a reminder, just don’t drink distilled water too much, and stay away from drinking contaminated distilled water.

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