Resources for parents to get through the challenges.

  1. Home
  2. Parenting

Does Distilled Water Go Bad?

Distilled water has many uses. Some people will drink distilled water daily and others will just use it occasionally in their humidifier or steam iron.

Whether you use distilled water regularly or not, there are a few important things that you should know about it – does distilled water go bad? How do you know if distilled water has gone bad? 

What Is Distilled Water?

Distilled water is different from regular tap water and bottled water. Distilled water has been through a distillation process to remove any impurities and minerals in the liquid.

Distilled water is made by boiling water and then condensing the evaporated steam back into a liquid in a separate container. This process can make the water taste different from usual forms of drinking water, it may taste flatter and have less flavor than bottled water. 

Distilled water can be bought from the grocery store or made at home using specifically designed steam distilling equipment. Distilled water is stripped of impurities but the distillation process will also remove all minerals from the water too.

Is It Safe To Drink Distilled Water?

Whilst the majority of people will just drink tap or bottled water, others choose to drink distilled water regularly. Distilled water is a form of purified water but unlike other forms of purified water, where only the toxins and impurities have been removed, distilled water is stripped of its minerals. 

As there are no minerals in distilled water, the water will absorb the minerals from anything it touches.

Some health experts argue that drinking distilled water is not good for the body as the water will try to draw the minerals it needs from your body’s own resources.

As there is no sodium or calcium and other vital minerals in distilled water, you may not be able to stay properly hydrated if it is the only water you drink. 

However, in countries where drinking water is dirty and full of toxins, drinking distilled water is the safer option. If you want to drink distilled water regularly, make sure you are also eating a diet rich in minerals so you do not develop any potential mineral deficiencies.  

Can Bacteria Grow In Distilled Water?

Bacteria will try and grow basically anywhere if it is given the chance. However, as distilled water is stripped of all of its minerals, bacteria will not be able to grow if the water is left unopened.

However, there is a risk that bacteria can enter the distilled water if the container is opened or the container is not sealed correctly.

It is unlikely that the bacteria will be able to successfully contaminate the water completely as distilled water does not provide a suitable environment for bacteria to grow and survive. 

Does Distilled Water Go Bad?

Distilled water can be stored unopened for years, some research even suggests distilled water can be stored indefinitely without going bad. However, manufactured distilled water will come with an expiration date, and homemade distilled water must be stored correctly to protect its longevity. 

Well, the answer to this will depend on what you are using the distilled water for. Distilled water itself doesn’t ‘go bad’ but it can be contaminated if left unopened or not stored correctly.

If you are using the water for appliances like steam cleaners, irons, humidifiers, and even car engines, you do not need to be overly concerned about the condition of the water.

Distilled water can be stored and regularly used for several years if it is only being used for appliances and not for human consumption. 

Store-bought distilled water often has an expiration date of around 3 to 5 years. However, many people will continue to store distilled water past its expiration date due to the fact it is difficult for contamination to occur in mineral sparse water, especially when left unopened. 

To keep your distilled water safe for longer, be sure to always store it away from sunlight in a tightly sealed container. Opened bottles of distilled water should be drunk within the same amount of time as regular bottled water, no more than a week after opening. 

Distilled water may not be easily contaminated by bacteria, but the water can ‘go bad’ in other ways. Distilled water will not only draw minerals from anything it touches but chemicals and toxins too.

If you store your distilled water in a plastic container for a long period of time, you run the risk of chemicals from the plastic being absorbed into the water.

Consuming chemicals from the plastic can be harmful so it is always best to store distilled water in glass bottles if you can or HDPE tanks for larger quantities. 

Does Distilled Water Go Bad In The Heat? 

To stop your distilled water from going bad, it is important it is stored away from direct heat and sunlight. Distilled water will go bad quicker when left in direct sunlight, especially when stored in plastic containers.

This is because it is easier for the plastic chemicals to seep from the bottle into the distilled water if the environment is warm. 

Does Distilled Water Go Bad After It’s Been Opened?

Like all water, the purity of distilled water will decrease once it has been opened. This is because contaminants are able to enter the water as soon as a bottle is opened and also because chemicals can seep into the water from the plastic container.

However, as there are no minerals in distilled water, it can be kept for longer than bottled mineral water once opened.

When stored in the refrigerator, an opened bottle of distilled water can last up to 9-12 months. However, when kept out of the refrigerator, distilled water will start going bad after around seven days. In comparison, unopened distilled water will not go bad for several years. 

Signs Distilled Water Has Gone Bad

If you follow all the guidelines set out in this article, you will keep your distilled water purer for longer and know when it is safe to drink and when it is not. However, if you are still unsure whether your distilled water has gone bad, here are a few signs to look out for:

Cloudy appearance

Distilled water should be clear. If you notice your distilled water looks at all cloudy, it has likely been contaminated with something and needs to be tipped away.

Green algae

Greeny-blue algae can grow in nutrient-rich water. However, as distilled water is stripped of nutrients and minerals, algae can only grow if the bottle has been left unopened.

If you notice algae growing in your distilled water, this will be due to it not being tightly sealed or left open for a prolonged period of time. Distilled water that has grown algae is no longer safe to drink and needs to be disposed of. 

Chemical or ‘off’ smell and taste

A general rule for all food and drink is if it smells off, it has probably gone bad and you shouldn’t risk it. If you notice a chemical smell in your distilled water, this may be down to the chemicals from the plastic that has leaked into the water.

Distilled water has a distinctively bland taste as it has no minerals providing flavor. If your distilled water has a distilled taste or even tastes a bit fishy or strange, it has been contaminated in some way and should not be consumed.


Does distilled water have a shelf life?

Unopened bottled distilled water bought from a store can in theory last forever. But it does need to be stored out of direct sunlight to prevent its deterioration.

Once it has been opened you need to ensure that it has been closed up well after. Although it can last forever in theory, store-bought distilled water will have an expiration date of between 3-5 years.

Does distilled water need to be refrigerated after opening?

Distilled water does not need to be refrigerated after opening. But you can if you want, it needs to be treated in exactly the same way as any other bottled water. We all know how refreshing cold glass of water right from the fridge is at the end of a busy day.

Does distilled water have chlorine?

Yes, it is possible that distilled water can contain chlorine. This is because chlorine can turn into a gas that is then filtered across.

Some manufacturers of distilled water leave the chlorine in their product because they do not have a VOC vent and an NSF-certified post-carbon filter.

The Final Thought 

Whether you are using distilled water for household appliances or you are drinking it regularly, it is important to store your distilled water correctly. When kept out of direct sunlight and stored in an airtight container, distilled water can last unopened for several years. 

Distilled water will start to deteriorate once opened or if stored incorrectly. If you have questions about other types of water such as coconut water and if it is safe for your children then check out our article here.