Many people wonder if stored water truly expires, often seeing expiration dates on bottled water. While these dates might suggest a limited shelf life, pure water (H2O) does not inherently “expire” like food. Instead, external factors and interactions with its container can influence its quality and safety over time.
The Truth About Water’s Expiration
Water is a stable chemical compound that does not “spoil” in the traditional sense. The U.S. Food and Drug Administration (FDA) does not require bottled water to have a shelf life, recognizing its inherent stability. The “expiration date” on bottled water typically refers to the degradation of the plastic bottle itself, not the water within. These dates can also be a result of regulatory requirements or inventory management. Tap water, when stored properly, can remain potable for extended periods.
What Makes Water Go Bad
While water itself does not expire, its quality can decline due to several factors. Chemical leaching from containers is a primary concern, as plastics can release compounds like Bisphenol A (BPA) or phthalates into the water, especially when exposed to heat or sunlight. These substances can affect the water’s taste and may pose health risks.
Microbial growth, including bacteria, algae, or fungi, can occur if water is exposed to air, light, or contaminants from handling. Warm temperatures accelerate microorganism multiplication.
Environmental contaminants, such as dust or dirt, can enter if containers are not properly sealed. The permeability of some plastic containers means that vapors from nearby chemicals can permeate the plastic and taint the water’s taste and odor.
Temperature fluctuations, particularly exposure to high heat or direct sunlight, accelerate both container degradation and microbial activity. Sunlight can also promote algae growth, especially in transparent containers.
Best Practices for Water Storage
Proper water storage is essential for maintaining its quality and safety. Selecting the right container is important; food-grade materials such as BPA-free plastic, glass, or stainless steel are recommended to prevent chemical leaching. Opaque containers are preferable, or stored water should be covered, to limit sunlight exposure, which can encourage algae growth and plastic degradation.
Containers should be stored in a cool, dark, and dry location, away from direct sunlight, chemicals, or strong odors. Ensuring containers are tightly sealed is important to prevent the entry of dust, dirt, and microorganisms. Thoroughly cleaning and sanitizing water containers is necessary before initial use or refilling.
For long-term storage of tap water, some suggest adding a small amount of unscented chlorine bleach to help maintain its purity, typically around 1/8 teaspoon per gallon, following specific guidelines. Stored water, especially tap water, should be rotated every six months to a year for optimal freshness.
How to Check Stored Water
Before consuming stored water, perform a quick sensory check to assess its quality. First, examine the water’s appearance for any signs of cloudiness, discoloration, or floating particles.
Next, smell the water for any unusual or foul odors, such as a musty, moldy, or chemical scent. Finally, while taste should be approached with caution, an unusual or metallic flavor is a clear sign of degradation.
If the water exhibits any concerning changes in appearance, smell, or taste, do not drink it. In such cases, the water can potentially be used for non-potable purposes, like watering plants if the issue appears minor, or it should be safely discarded if heavily contaminated.