Is the expiration date for the water or the bottle?
The expiration or "best by" date on still water bottles is primarily a guideline for optimal taste and freshness, not an indicator of the water's safety. The concern isn't with the water chemically spoiling, but rather with the plastic bottle itself, particularly polyethylene terephthalate (PET). Over time, especially when exposed to heat and sunlight, this plastic can degrade.
The issue with plastic bottles
Plastic degradation can lead to the leaching of trace chemicals into the water, potentially altering its taste. While these levels are generally considered safe by the FDA, they can cause an undesirable "plastic-like" flavor. Heat significantly speeds up this process, making it unwise to leave bottled water in a hot environment like a car. There are ongoing studies into the long-term health effects of microplastics and leached chemicals.
Factors that influence bottled water quality over time
Several environmental factors can affect the quality of still water in a sealed bottle. Optimal storage is key to maintaining freshness.
- Temperature: High temperatures accelerate plastic degradation and taste alteration. Storing water in hot places like garages or attics is discouraged. A cool, room temperature environment is ideal.
- Sunlight exposure: UV light from direct sunlight can speed up plastic breakdown and chemical leaching. Store bottles in a dark place.
- Proximity to chemicals: Plastic can be porous, allowing vapors from nearby chemicals like cleaners or fuels to affect the water's taste and odor. Store water away from such substances.
- Container material: The material matters. Glass or stainless steel containers are more durable and less prone to leaching than standard PET plastic bottles, offering better long-term purity.
A comparison of water storage containers
| Feature | PET Plastic Bottles | Glass Containers | Stainless Steel Containers |
|---|---|---|---|
| Cost | Low | High | High |
| Durability | Low; can crack or leak over time. | High; can break if dropped. | High; resistant to impact. |
| Chemical Leaching | Possible, especially with heat exposure. | None. | None. |
| Impact on Taste | Potential for "plastic" taste over time. | No impact on taste. | No impact on taste. |
| Long-Term Storage | Two years recommended for best quality. | Indefinite (if sealed and stored properly). | Indefinite (if sealed and stored properly). |
Best practices for storing still water
Proper storage is essential for preserving the quality of still water, whether for regular use or emergencies.
- Choose suitable containers: Use food-grade, sealable containers. Glass or high-quality plastic is preferable for long-term storage. Avoid reusing single-use bottles due to potential bacterial issues.
- Select the right location: A cool, dark place with a consistent temperature is ideal. Basements or cupboards are better choices than garages or attics.
- Maintain cleanliness: Ensure bottles are clean and stored away from chemicals. Labeling with storage dates helps manage stock.
- Rotate your stock: For emergency supplies, the Red Cross advises replacing commercial bottled water annually. The CDC recommends replacing home-filled tap water every six months.
- Inspect before drinking: Before consuming water stored for extended periods, check for off-odors, strange tastes, cloudiness, or any bottle damage.
Conclusion: Still water lasts, but its package doesn't
Still water itself has a practically indefinite shelf-life. The "best by" date indicates the packaging's ability to maintain optimal taste, not a safety limit. Water quality is heavily influenced by proper storage, particularly protection from heat, sunlight, and contaminants. By following good storage practices, you can keep your water fresh and safe for years. For more on water safety, consult the CDC.
How to create and store an emergency water supply guide
Setting up an emergency water supply is a practical step for preparedness.
- Select containers: Use food-grade containers that can be sealed, like heavy-duty plastic jugs or glass jars.
- Clean thoroughly: Wash containers with hot, soapy water, rinse, and sanitize with a bleach solution (1 tsp unscented chlorine bleach per quart of water).
- Fill with water: If using tap water from a public supply, you can fill directly as it contains chlorine.
- Label clearly: Mark containers as “drinking water” and include the storage date.
- Store properly: Keep water in a cool, dark, dry place, away from chemicals or fuels.
- Replace periodically: Rotate your stored water every six months to a year, depending on the container type.
- Calculate needs: Store at least one gallon of water per person per day for drinking and hygiene.
The differences in still water types
While the pure water is stable, the type can sometimes relate to processing and potential storage considerations.
- Purified water: Treated to remove impurities from various sources, making it very stable for storage.
- Spring water: Comes from a natural underground source with a distinct mineral profile. Its longevity is mostly determined by its packaging.
- Mineral water: Sourced from protected underground formations with a stable mineral content. Packaging is the key factor for its shelf life as its composition is not altered.
- Tap water: Contains chlorine for disinfection, which dissipates over time, potentially allowing bacterial growth. It requires more frequent replacement in storage than commercially bottled water.
Potential risks of drinking improperly stored water
Poor storage can compromise water quality beyond just taste.
- Bacterial contamination: Opened bottles are susceptible to airborne bacteria, which can multiply, especially in warm conditions. Reusing single-use plastic bottles increases this risk.
- Chemical leaching: Heat and sunlight can cause plastic to break down and release trace chemicals into the water. While typically within safety limits, it can affect taste and is a long-term health concern for some.
- Algae growth: Though uncommon in sealed, properly stored bottles, light exposure can potentially lead to algae growth.
What to do if your water tastes or smells bad
If stored water has an unpleasant taste or smell, it's best to discard it. Boiling can address bacteria but won't remove chemicals from degraded plastic. Shaking stored tap water can help improve its taste by re-oxygenating it.
Can you drink expired bottled water safely?
Generally, yes, if it's been sealed and stored correctly. The date is a quality indicator, not a safety cutoff. However, discard if the taste or smell is off.
When should you throw out bottled water?
Discard bottled water if you observe any of the following:
- Cloudiness or discoloration: Potential contamination or algae.
- Odd smells: Indicates degraded water quality.
- Unpleasant taste: Not worth the risk or discomfort.
- Bottle damage: Compromised seal affects purity.
A note on sustainability
Given concerns about plastic, consider sustainable alternatives. Refillable glass or stainless steel containers with filtered tap water reduce plastic waste and leaching risks. Home filtration systems provide fresh water on demand, lessening the need for long-term plastic storage.
Conclusion
While still water itself is chemically stable with an indefinite shelf-life, the quality and taste of bottled water are limited by its packaging and storage conditions. Proper storage in a cool, dark place and stock rotation ensure fresh, safe drinking water for years. Understanding that the expiration date pertains to the bottle, not the water, helps in making informed hydration choices.
