Does Purified Water Expire?
The question of whether purified water has an expiration date is a common one, particularly for those who rely on it regularly. This article aims to clarify this concern, detailing the factors that contribute to the shelf life of purified water and how to properly store it.
Storage Conditions and Potential Risks
When stored properly, purified water can maintain its purity for extended periods. However, it's important to understand that purified water, especially when stored in plastic containers, can be susceptible to certain risks. The leading risk is chemical leaching from the plastic, which can occur under certain conditions. Specifically, storing water in plastic containers at temperatures above 153°F (67°C) can cause harmful chemicals to leach into the water, posing health risks to consumers.
One must also be wary of exposure to plasticizers and metal leaching, which can occur even at room temperature if the water is left in direct contact with the plastic container for prolonged periods.
Expiration Dates of Different Types of Purified Water
The expiration date of purified water can vary depending on its intended use. For instance, medical-grade purified water, such as saline, often comes with a specific expiration date, as it is regulated for medical use. Similarly, food-grade purified water also has a best before date, as it is intended for human consumption. On the other hand, water used for radiator coolant or to top up lead acid batteries does not have an expiration date, as its primary purpose is to provide a protective layer rather than for human consumption.
For bottled water or tap water intended for drinking, a best used by date is mandatory as per the FDA (Food and Drug Administration) regulations. According to these regulations, clean bottled water with an unbroken seal is generally safe to consume for about two years. However, prolonged exposure to air, contaminants, and dust can degrade the quality of the water over time.
Factors Affecting the Purity of Purified Water
Several factors can affect the purity of purified water, even if it is stored in a sealed container. When left open for extended periods, gases from the surrounding environment can dissolve into the water, along with dust particles and undesirable electrolytes. These contaminants can alter the purity, making the water unsuitable for specific uses.
In addition, algae can grow within the container walls, further reducing the water's purity and analytical grade, especially if the water is used for critical laboratory applications. Moreover, the use of unclean or wet pipettes to dip into bulk storage containers can introduce impurities, compromising the water's suitability for analytical purposes.
Proper Storage of Purified Water
To ensure that purified water maintains its quality and purity, it is crucial to store it in a tightly sealed container. The container should be protected from direct sunlight, as exposure to light can cause some plastics to degrade, potentially leading to the release of harmful substances.
Plastic containers, in particular, are less durable and more likely to leach chemicals when exposed to high temperatures or environmental contaminants. In contrast, glass containers can maintain the purity of purified water for extended periods when stored correctly.
Sprague A, a noted authority in the field, has provided insights on the proper handling and storage of purified water. It is imperative to follow best practices, such as using clean and dry containers, keeping the water sealed, and avoiding contamination from dust and air. These measures are essential to protect the quality of the water and ensure it remains safe for consumption or specific uses.
Furthermore, it is essential to note that storage conditions can vary between different settings, such as warehouses or transportation vehicles. While it is true that warehouses can be hot, modern warehouses typically have air conditioning to maintain optimal temperatures. Similarly, during transportation, such as in delivery trucks, the temperature of water bottles is less affected by the external environment. Evidence shows that even in hot climates, water delivery trucks can maintain cool temperatures, ensuring the purity of the water when delivered to consumers.
Conclusion
In summary, purified water does have an expiration date, depending on its intended use and storage conditions. To ensure the purity and safety of purified water, it is essential to store it properly, especially when using plastic containers. Following these guidelines will help maintain the quality of the water, making it suitable for consumption or various applications.
By understanding the factors that affect the expiration of purified water and taking appropriate storage measures, you can enjoy safe, high-quality water for years to come.