Can Water Expire? Everything You Need to Know About Water Shelf Life

If you’ve ever grabbed a bottle of water from your pantry or emergency supply and noticed an expiration date stamped on the label, you might have wondered: can water actually go bad? After all, water is a simple compound of hydrogen and oxygen that has existed on Earth for billions of years.

The answer isn’t as straightforward as you might think. While pure water (H2O) itself doesn’t spoil or expire in the traditional sense, several factors can affect the safety and quality of the water you drink. This comprehensive guide explores everything you need to know about water expiration, storage, and safety.

Understanding Water Expiration Dates

The expiration dates you see on bottled water aren’t actually about the water itself going bad. In fact, water is a stable substance that doesn’t decompose or spoil like food products do. So why do water bottles have expiration dates?

Historically, New Jersey became the first U.S. state in 1987 to mandate expiration dates on all food products, including bottled water. The law required a 2-year maximum shelf life from the manufacturing date. Although this specific legislation was eventually revised and is no longer in effect, the practice became an industry standard that manufacturers continue to follow voluntarily.

Today, bottled water companies print expiration dates primarily for quality control purposes and to comply with various state regulations. These dates typically range from 1 to 2 years from the bottling date, but they’re more of a “best by” recommendation than a strict safety deadline.

Does Tap Water Go Bad?

Tap water that has been properly stored can remain safe to drink for approximately 6 months. However, its taste and quality may change over time due to several factors:

Changes in Taste: When tap water sits exposed to air, carbon dioxide from the atmosphere gradually dissolves into it, forming carbonic acid. This process makes the water slightly more acidic and can create a stale or flat taste. While this might not be pleasant, it doesn’t necessarily mean the water is unsafe to drink.

Loss of Chlorine: Municipal tap water contains chlorine as a disinfectant. Over time, this chlorine dissipates, which can leave the water more vulnerable to bacterial growth if it becomes contaminated.

Temperature Considerations: Water stored at room temperature provides a more hospitable environment for bacterial growth compared to refrigerated water. However, if the water was clean when stored and the container remains sealed, bacterial contamination is unlikely.

Why Bottled Water Can Actually Expire

While the water inside a bottle doesn’t technically expire, the plastic container itself poses potential problems over time. Here’s what happens:

Chemical Leaching from Plastic

The primary concern with drinking bottled water past its expiration date relates to the plastic container rather than the water itself. Plastic bottles can gradually leach chemicals into the water, especially under certain conditions. These chemicals include:

• Antimony: A toxic metalloid used in the production of polyethylene terephthalate (PET) plastic bottles
• Bisphenol A (BPA): An industrial chemical used in some plastics that can disrupt hormonal function
• Microplastics: Tiny plastic particles that break down from the container
• Phthalates: Chemicals used to make plastics more flexible

Research indicates that the amount of chemical leaching increases with time, temperature, and exposure to sunlight. While the levels found in recently bottled water are generally considered safe by regulatory standards, long-term accumulation of these compounds in your body could potentially impact your health.

Potential Health Impacts

Regular consumption of water contaminated with plastic chemicals may affect various aspects of health, including:

• Endocrine system disruption
• Reproductive health concerns
• Immune system function
• Gut microbiome balance
• Respiratory health

It’s important to note that more research is needed to fully understand the long-term health effects of low-level plastic chemical exposure from bottled water.

How Long Does Water Really Last?

The shelf life of water depends primarily on how it’s stored and what type of container it’s in:

Commercially Bottled Water

Unopened bottled water stored properly can last 1-2 years past the printed expiration date without significant quality degradation. However, for optimal safety and taste, it’s best to consume it within the timeframe indicated on the label.

Tap Water in Storage

When properly stored in clean, food-grade containers, tap water remains safe for consumption for up to 6 months. After this period, while it may still be safe, the taste quality can deteriorate.

Opened Bottled Water

Once opened, bottled water should be consumed within 3-5 days if stored in the refrigerator. Bacteria from your mouth can contaminate the water when drinking directly from the bottle, leading to faster bacterial growth.

Sparkling or Carbonated Water

Carbonated water has a shorter shelf life regarding quality. The carbon dioxide gas that creates the bubbles gradually escapes over time, even in sealed containers. While flat carbonated water is safe to drink, it loses its characteristic fizz and may taste stale. Opened carbonated water goes flat within 1-2 days.

Proper Water Storage Guidelines

Whether you’re preparing an emergency water supply or simply want to maximize the shelf life of your drinking water, proper storage is essential. Follow these best practices:

For Tap Water Storage

• Use appropriate containers: Choose food-grade water storage containers made of materials approved for drinking water. Glass, stainless steel, or BPA-free plastic containers work well.
• Clean and sanitize: Thoroughly wash containers with dish soap and water, then sanitize with a diluted bleach solution (1 teaspoon of unscented household bleach per quart of water). Rinse completely.
• Fill properly: Fill containers to the top to minimize air space, which can promote bacterial growth.
• Label clearly: Mark each container with the filling date and contents to track storage time.
• Choose the right location: Store in a cool, dark, dry place away from direct sunlight and heat sources.
• Keep away from chemicals: Store water away from gasoline, pesticides, and household cleaning products, as vapors can permeate some containers.

For Bottled Water Storage

• Maintain cool temperatures: Store at room temperature or cooler, ideally between 50-70°F (10-21°C).
• Avoid sunlight: UV rays accelerate chemical leaching from plastic and can promote algae growth.
• Don’t freeze: Freezing can damage plastic bottles and potentially increase chemical leaching when thawed.
• Keep sealed: Don’t open bottles until ready to use to prevent contamination.
• Rotate stock: Practice “first in, first out” to use older bottles before newer ones.
• Avoid car storage: Don’t leave bottled water in hot cars, where temperatures can soar and accelerate plastic degradation.

Signs Your Water May Have Gone Bad

While properly stored water rarely becomes unsafe, watch for these warning signs that indicate you should discard the water:

• Unusual odor: A musty, plastic-like, or chemical smell suggests contamination or excessive chemical leaching.
• Off taste: While slight staleness is normal, any strong or unpleasant taste is a red flag.
• Cloudiness or particles: Clear water that becomes cloudy or contains floating particles should not be consumed.
• Visible growth: Any signs of algae, mold, or biofilm formation mean the water is contaminated.
• Damaged container: Cracks, leaks, or significant deformation of the storage container can allow contamination.
• Changed color: Any discoloration indicates potential contamination.

Alternatives to Plastic Bottled Water

To avoid concerns about plastic chemicals and expiration dates altogether, consider these alternatives:

Reusable Water Bottles

Invest in high-quality reusable bottles made from:

• Stainless steel: Durable, doesn’t leach chemicals, and maintains temperature well
• Glass: Doesn’t impart flavors, completely inert, and easy to clean
• BPA-free plastic: Lighter weight option without harmful BPA

Home Water Filtration

Installing a water filtration system provides fresh, clean water on demand:

• Pitcher filters for basic filtration
• Faucet-mounted filters for convenience
• Under-sink systems for comprehensive filtration
• Whole-house filters for complete home water treatment

Water Delivery Services

Large-format water delivery in 3- or 5-gallon containers reduces plastic waste and ensures fresh water regularly.

Emergency Water Storage Considerations

For emergency preparedness, proper water storage is crucial. Emergency management agencies recommend storing at least one gallon of water per person per day for a minimum of three days.

Tips for Emergency Water Supply

• Store a two-week supply if space allows
• Rotate water every 6 months to maintain freshness
• Consider water purification tablets or portable filters as backup
• Know how to purify water through boiling (rolling boil for 1 minute)
• Keep bleach on hand for emergency water disinfection (8 drops per gallon of clear water)

Environmental Considerations

Beyond personal health concerns, the expiration and disposal of bottled water has significant environmental implications:

Plastic Waste: Americans use approximately 50 billion plastic water bottles annually, with only about 23% being recycled. The rest end up in landfills or as environmental pollution.

Production Impact: Manufacturing plastic bottles requires significant energy and resources, including petroleum and water.

Transportation Emissions: Shipping bottled water across the country generates substantial carbon emissions.

Choosing reusable bottles and home filtration systems can significantly reduce your environmental footprint while also eliminating concerns about water expiration dates.

Frequently Asked Questions

Can I drink water that’s been sitting out overnight?

Yes, water left out overnight is generally safe to drink, though it may taste slightly stale due to carbon dioxide absorption from the air. If the water was in a clean glass or bottle, there’s minimal risk of contamination.

Is expired bottled water safe in emergencies?

In emergency situations where no other water source is available, expired bottled water is typically safer than potentially contaminated water sources. The risks from plastic leaching are generally less immediate than dehydration or waterborne illness.

Does boiling water extend its shelf life?

Boiling water kills bacteria, viruses, and parasites, making it safer for immediate consumption. However, boiling doesn’t extend shelf life unless the water is then stored in sterile, sealed containers. Boiled water should be stored the same way as unboiled tap water.

Can I store water in old juice or milk containers?

It’s not recommended to reuse containers that held milk, juice, or other beverages for water storage. Residual sugars and proteins can promote bacterial growth even after washing. Use containers specifically designed for water storage.

The Bottom Line

Water itself doesn’t expire, but the containers we store it in and the conditions it’s kept under can affect its safety and quality over time. Tap water properly stored in clean containers remains safe for up to 6 months, while commercially bottled water is best consumed within its printed expiration date to avoid potential chemical leaching from plastic.

The key to safe water consumption is proper storage: keep water in a cool, dark place, away from chemicals and direct sunlight. Whether you choose tap water, bottled water, or filtered water, following these guidelines ensures you always have access to safe, refreshing drinking water.

For the most sustainable and health-conscious approach, consider investing in reusable water bottles and a home filtration system. This eliminates concerns about expiration dates, reduces plastic waste, and provides you with fresh, clean water whenever you need it.

Remember, staying properly hydrated is essential for your health, so don’t let concerns about water expiration prevent you from drinking enough water throughout the day. When in doubt about water quality, trust your senses—if it looks, smells, or tastes off, it’s better to err on the side of caution and find an alternative source.

Sources:

• FDA – Bottled Water Everywhere: Keeping it Safe
• EPA – Ground Water and Drinking Water
• CDC – Bottled Water Information
• Ready.gov – Water Storage for Emergencies
• NCBI – Antimony in PET Bottled Drinking Water
• WHO – Drinking Water Fact Sheet