Can distilled water go bad?

distilled water gone bad

Distilled water can go bad. An unopened bottle of distilled water can last anywhere from 3 to 5 years. If you’ve opened the bottle for drinking, then you should drink it within 4 to 7 days. If you’re going to be using distilled water for appliances, an opened bottle with a lid will last for over 2 years before it expires. But most likely you will finish it by that time anyway.

Let’s dig deeper to cover a few additional points about distilled water. Keep in mind that this article discusses the uses of distilled water for household purposes mostly. If you’re using distilled water for motor industry or medical work-related purposes – you should follow your field guidelines.

How long does distilled water last

Well, it mostly depends on the way you use and store it. The shelf life of distilled water will be on the label. Average times can be summed up in the following table.

Commercially bottled distilled water (unopened)5+ years
Commercially bottled distilled water (opened, for appliance use)2+ years
Commercially bottled water (opened, for drinking)4 – 7 days
Home-distilled water4 – 7 days

As with any drinking water, these things will affect its properties:

• The storage temperature

• Exposure to light

• Type of the container it is kept

• Exposure with air and surfaces

• Contamination with mouth bacteria

We’ll address these more in detail later, but let’s sum up how long you should keep distilled water and the reasons of its expiration.

Commercially bottled distilled water has a shelf life that can last pretty much indefinitely because it was poured and sealed in a clean environment. With the condition that it remains unopened and stays in an airtight environment where contamination is impossible. Although store-bought bottled water may indeed last for years before the expiry date, ideally you should consume it at some point and replace it with a fresh batch. Prolonged storing most likely will affect the taste. As for other properties, like the overall quality, the water will be water and will be good to drink, unless it becomes contaminated.

The same goes for home distilled water. If you managed to produce and bottle it in a highly sterile environment, it should be good to store for a long time. But that takes a lot of effort and is not really worth it. Simply distill water and use it in the following week.

Megahome Countertop Water Distiller

Snugell distilled water

How to tell if distilled water has gone bad

• Bad smell
• Floating particles
• Cloudiness

The unpleasant smell is the most likely result of water that’s gone bad. When drinking, especially in warmer climates, make sure to use a glass or something meant to pour water into. When you sip directly from the bottleneck, a tiny fraction of natural mouth bacteria gets inside the bottle and they start multiplying. The warmer temperature is what mostly affects how fast the microorganisms will begin to multiply by large numbers.

If unopened, the water stays clear of air and stays freshly sealed inside the container so it can last for quite a while. In general, distilled water is really pure, which means that even slight intrusions like air and various microparticles can enter it and alter the smell ever so slightly. If you don’t work in a lab environment, this is nothing to worry about. Unless you have a clear suspicion that the water is contaminated and it smells wrong, then simply get rid of it.

How to store distilled water

• Low and stable temperature

• No or minimal exposure to sunlight

• Glass containers with tight lids

Glass bottles of water

The storage method for store-bought distilled water is similar to other types of bottled water. If you own a water distiller and are distilling water at home for drinking, then reusable glass containers are the best idea. Glass is a very robust and hard to alter material that does not react with water. However, it can break so it might not be ideal for an everyday drinking canteen. A plastic BPA-free food-grade bottle is your second best choice.

If you’re storing homemade or store-bought, distilled water long term, then simply follow these guidelines.

An unopened bottle should be kept in a cool, dry, and dark place away from direct sunlight and heat. Keep the same guidelines as you would for any other packaged food and beverage, which means that a kitchen pantry or cabinet is ideal. Also, a dry and clean garage or basement might be the right place.

Just don’t leave bottles in your car for too long, especially during the hot days.

When it comes to distilled or purified water meant for home appliances, as mentioned, it will last indefinitely if unopened. If opened, not contaminated, and stored correctly, it can last for over two years. Afterall all, there’s no point in getting stressed that the water for your steam iron will damage the appliance in any way.

How can I use expired distilled water?

You can use it in the same normal way. The shell life of distilled water has to be there for a few reasons. 

Firstly, food and drink manufacturers have to put expiration dates on labels, otherwise, it makes responsible agencies and consumers concerned when people can’t find an expiration date. Something that expires means that’s food or drink. Something that does not expire is not thought of as edible.

Secondly, water is one of the primary elements that our bodies and much of our planet is made of. In essence pure H2O is stable and if kept in a perfectly secure container that is not reactive it will remain as it is, unchanged for thousands of years.

However, the container most often is the issue. If distilled water is kept in plastic bottles for too long, like tens of years, theoretically some micro amount of plastic can leach into the water. Also if the distilled water container was open and water gets a sufficient amount of contaminants some microorganisms can start multiplying in there. These two are the most probable reasons why distilled can get bad.

But in general, distilled, after it’s expiration date, can still be used in a CPAP machine or a neti pot. Just keep the same guidance as you would while using water in these devices.

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