Does Distilled Water Go Bad? A Comprehensive Guide to Its Shelf Life

logo by Editorial Staff | Updated on September 21st, 2023

Are you pondering the shelf life of distilled water? Whether you’ve stocked up for an emergency, use it in household appliances, or consume it for health benefits, knowing how long it lasts is vital. This in-depth guide explores the longevity, proper storage methods, and various uses of distilled water. Read on to find everything you need to know.

Does Distilled Water Expire?

The straight answer is that distilled water, when stored correctly, can last indefinitely. Unopened bottles or containers of distilled water don’t have an expiration date, making them an excellent choice for long-term storage. If opened, however, its longevity varies based on its intended use and storage conditions. For drinking, it’s advisable to consume opened distilled water within a week to avoid any contamination risks.

distilled water
Bottled distilled water (unopened)5+ years
Bottled distilled water (opened for appliance use)1+ years
Bottled distilled water (opened for drinking)4 – 7 days
Home-distilled water4 – 7 days

How Long Does Distilled Water Last Once Opened?

The life span of an opened container of distilled water depends heavily on its usage. If you’re planning to drink it, it’s best to consume it within 4-7 days to ensure it remains uncontaminated. For non-consumption purposes, such as using it in household appliances like humidifiers or irons, you can expect it to last up to a year if stored under ideal conditions.

The Impact of Temperature on Distilled Water

Temperature is a critical factor in determining the shelf life of distilled water. Keeping it in a cool, dry place away from direct sunlight is paramount. Exposing distilled water to heat or sunlight, especially if stored in plastic containers, can accelerate the degradation process. Heat can cause the plastic to leach into the water, reducing its purity over time.

Is Refrigeration Required for Opened Distilled Water?

Contrary to popular belief, refrigerating opened distilled water isn’t necessary. While a cold glass of water may be refreshing, distilled water doesn’t require refrigeration to maintain its quality. However, if you decide to refrigerate it, make sure to treat it like any other type of bottled water, ensuring the bottle is sealed well to avoid contamination.

Understanding the Nature of Distilled Water

Distilled water is water that has undergone a purification process, where it’s boiled and then condensed back into a liquid form, free of most contaminants. This makes it a popular choice for drinking, cooking, and even medical applications. However, distilled water is not entirely devoid of all contaminants; trace amounts may still exist but are generally considered negligible.

The Process Behind Distillation

Water from various sources—be it a natural spring, tap, or well—is subject to contamination. Distillation effectively eliminates 99.9% of these, making it one of the purest forms of water. The process involves boiling the water and capturing the steam, which is then cooled and condensed back into liquid, thus leaving most contaminants behind.

Best Storage Practices for Distilled Water

When it comes to storing distilled water, a few principles can help maintain its longevity and purity. Keep it in a cool, dark place, such as a basement or pantry. For long-term storage, use glass or BPA-free plastic containers with tight-fitting lids. This ensures that no contaminants can get in, and it reduces the risk of water-absorbing flavors or odors.

How To Tell If Distilled Water Has Gone Bad

Even though distilled water is highly purified, it’s still susceptible to contamination if not stored properly. Indicators of spoilage include a musty odor, strange taste, or any signs of algae or mold growth. If you notice any of these signs, it’s best to dispose of the water to avoid health risks.

Uses of Distilled Water

Besides drinking, distilled water has a multitude of other uses. It is commonly used in:

  • Household appliances: Such as steam irons and humidifiers
  • Automotive maintenance: For topping up lead-acid batteries
  • Medical applications: Sterilization and cleaning of medical equipment
  • Aquariums: Where tap water might be too impure
  • Cooking: For recipes that require water free from minerals and impurities

Is Distilled Water Suitable for Everyone?

Although distilled water is a popular choice for many, it’s worth noting that its absence of minerals can be a downside for some. People with specific health conditions may require those essential minerals found in other types of water. Pregnant women and those with certain medical conditions should consult their healthcare provider before making a switch to distilled water for consumption.


In a nutshell, distilled water doesn’t expire, making it an excellent option for long-term storage and various applications. However, like any other type of water, it can become contaminated if not stored correctly. Adhering to proper storage methods and paying attention to the signs of spoilage will ensure that your distilled water remains as pure as possible for an extended period.

There you have it, a comprehensive guide on the shelf life of distilled water. Whether you plan to drink it, use it in household appliances, or keep it as part of an emergency preparedness plan, knowing how to store and identify spoilage can go a long way. 


Editorial Staff

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