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Glass jars can safely hold water in many home situations, but they are not the best choice for every type of water storage. Clean, food-safe glass does not normally react with water, and it does not absorb odors or flavors. The bigger concerns are breakage, freezing, light exposure, lid condition, and contamination during filling or use.
For a small amount of drinking water kept in a refrigerator or cupboard, a clean glass jar with a tight lid can work well. For emergency supplies, large volumes, outdoor storage, or rainwater tanks, stronger food-grade containers are usually more practical.
Is Glass Safe for Storing Drinking Water?
Yes. The glass itself is generally suitable for storing drinking water when the jar:
- Was made for food or beverage use
- Is clean and properly sanitized
- Has no cracks or chips
- Has a lid that closes tightly
- Has never held toxic chemicals
- Is stored where it will not freeze or be easily knocked over
The water going into the jar must also already be safe for its intended use.
This last point matters with rainwater. Putting roof runoff into a clean glass jar does not make the water safe to drink. Roof runoff can contain microorganisms, dirt, animal waste, roofing residues, metals, and other contaminants.
For drinking-water storage, the container protects water that is already suitable for drinking. It is not a treatment system.
Why Glass Can Be a Good Water Container
Glass has several useful qualities for small-scale water storage.
Glass does not absorb odors
Unlike some plastics, glass does not easily hold smells or flavors from previous contents. A properly cleaned jar can therefore be useful for storing drinking water.
It is easy to inspect
Because most household jars are clear, you can see sediment, discoloration, or visible growth.
That does not mean clear water is necessarily safe. Many microorganisms and dissolved contaminants cannot be seen.
It is easy to clean
Wide-mouth jars are especially easy to wash because you can reach the inside surfaces.
A narrow bottle may be harder to clean thoroughly unless you have an appropriate bottle brush.
Glass works well for small quantities
A few jars in a refrigerator or pantry can be convenient. The problems with glass become much more important when you try to store dozens of gallons.
The Main Problems With Glass Water Storage
The biggest drawbacks are physical rather than chemical.
Glass can break
This is the main reason glass is a poor choice for many emergency water supplies.
Current CDC emergency water-storage guidance recommends food-grade storage containers and says that, when those are unavailable, containers should be durable and unbreakable rather than glass.
A broken jar causes two problems at once. You lose the water, and you now have broken glass around an area where you may already be dealing with an emergency.
Glass is especially inconvenient in:
- Vehicles
- Garages
- Sheds
- Earthquake-prone areas
- Shelves above floor level
- Cabins that are left unattended
- Outdoor rainwater systems
Glass is heavy
Water already weighs about 8.3 pounds per gallon. Glass adds even more weight.
Several cases of filled jars can put a significant load on shelving. Keep large quantities low to the floor and use shelving that can safely support the load.
For tens or hundreds of gallons, a purpose-built water container is much more practical than individual jars.
Clear glass lets light reach the water
Light does not automatically make stored water unsafe, but it can encourage biological growth when microorganisms and nutrients are present.
This is particularly relevant to untreated rainwater.
Store clear jars away from direct sunlight. CDC guidance likewise recommends keeping stored drinking water in a cool location away from direct sunlight.
Opaque storage tanks and containers have an advantage for rainwater because they greatly reduce light entering the water.
Glass can crack when water freezes
Water expands as it freezes. A full jar may crack or shatter when this happens.
Do not leave filled glass jars where temperatures may fall below freezing.
This includes:
- Unheated garages
- Outdoor sheds
- Cabins during winter
- Vehicles
- Outdoor rainwater storage areas
Even leaving extra space in the jar does not make glass storage completely safe from freeze damage. Containers exposed to freezing conditions should be chosen and protected specifically for that environment.
What Kind of Glass Jar Should You Use?
Use jars intended for food or beverage storage.
Mason-style canning jars are usually a better choice than thin decorative bottles because they are designed for repeated food use and are relatively sturdy. However, they can still break.
Reused food jars can also work if they are in good condition. A jar that previously held pasta sauce, pickles, or another food is very different from a container that held chemicals.
Never use a jar or bottle that previously contained:
- Pesticides
- Fuels
- Solvents
- Automotive chemicals
- Cleaning chemicals
- Other toxic substances
CDC guidance specifically warns against using water-storage containers that previously held toxic chemicals.
When the previous contents are unknown, choose another container.
Pay Attention to the Lid
The jar may be glass, but the lid usually is not.
A poor lid can become the weak point of the storage system.
Check that the lid:
- Fits correctly
- Creates a reliable closure
- Has no rust
- Has no damaged coating
- Has no strong remaining food odor
- Is clean around the threads and seal
Check safe emergency water storage to compare service needs that influence lifecycle performance.
Metal lids may eventually corrode in damp conditions. If the underside of a lid is rusty, damaged, or deteriorating, replace it rather than continuing to use it for drinking-water storage.
A tight lid also helps protect stored water from dust, insects, hands, and other sources of contamination.
How to Prepare Glass Jars for Water Storage
A clean-looking jar is not necessarily sanitary.
Before filling a jar intended for drinking-water storage, wash and sanitize it appropriately.
CDC guidance for water-storage containers calls for washing with soap and water, rinsing thoroughly, sanitizing the inside surfaces, and then filling the sanitized container with clean water before closing it tightly.
After preparing the jar:
- Fill it with water that is already suitable for drinking.
- Avoid touching the inside of the jar or lid.
- Close it tightly.
- Label it as drinking water.
- Add the storage date.
- Store it somewhere cool and dark.
CDC currently recommends replacing home-filled emergency drinking water every six months.
That recommendation is particularly useful for emergency supplies that may sit unused for long periods.
Can You Store Rainwater in Glass Jars?
Yes, but the intended use matters.
Rainwater for plants
A glass jar can hold small quantities of rainwater for houseplants or other limited garden use.
It is usually unnecessary for larger amounts. A rain barrel, IBC tote, or cistern is far more practical.
Rainwater for cleaning or other non-potable uses
Glass can hold rainwater temporarily, but larger containers make more sense for routine household reuse.
Non-potable means water that is not intended for drinking.
Rainwater for drinking
A glass jar does not solve the water-quality issues associated with roof runoff.
Rainwater intended for drinking needs to be considered as part of a whole system. Depending on the system and local requirements, that may include suitable roof and gutter materials, debris control, a first-flush system, protected storage, filtration, disinfection, regular maintenance, and current laboratory testing.
A first flush device diverts some of the first runoff from a roof so that accumulated dirt and debris do not immediately enter the main storage tank.
Even boiling or disinfecting questionable water has limits. EPA notes that these methods can kill many disease-causing microorganisms but do not remove contaminants such as heavy metals, salts, and many chemicals.
Do not judge the safety of stored rainwater only by whether it looks, smells, or tastes normal.
Is Glass Better Than Plastic for Water Storage?
Neither material is best in every situation.
| Situation | Glass | Food-Grade Plastic |
|---|---|---|
| Refrigerator water | Good choice | Good choice |
| Small pantry supply | Good choice | Good choice |
| Large emergency supply | Poor to fair | Usually better |
| Outdoor storage | Poor | Usually better |
| Freezing location | Poor | Depends on container |
| Rain barrel or cistern | Impractical | Common choice |
| Easy visual inspection | Excellent | Depends on container |
| Resistance to breakage | Poor | Good |
For a pitcher or several jars of household drinking water, glass can be very convenient.
For a two-week emergency supply or a rainwater system holding dozens or hundreds of gallons, durable food-grade storage containers are usually the better fit.
CDC identifies unopened commercially bottled water as the safest and most reliable emergency water source and recommends FDA-approved food-grade containers when people prepare their own stored supply.
Where Should Glass Water Jars Be Stored?
Choose a location that is:
- Cool
- Dark
- Dry
- Protected from freezing
- Protected from impacts
- Away from gasoline, pesticides, and other chemicals
- Supported by strong shelving
Avoid sunny windowsills. Sunlight can warm the water and provides light that biological growth may use.
Also avoid storing drinking water next to chemicals. CDC advises keeping water-storage containers away from toxic materials such as gasoline and pesticides.
When Glass Jars Make Sense
Glass jars are most useful when you need a modest amount of water indoors.
They are a reasonable choice for:
- Refrigerated drinking water
- A few jars kept in a kitchen cupboard
- Short-term storage of treated water
- Small amounts of non-potable rainwater
- Situations where easy cleaning is important
Use another type of container when you need:
- Many gallons of emergency water
- Outdoor storage
- Portable water
- Vehicle storage
- Freeze-resistant storage
- A rain barrel
- A large cistern
- Water that may be moved frequently
The best container is not simply the material that can hold water. It needs to fit the amount of water, the storage location, the expected temperature, and how the water will eventually be used.
Frequently Asked Questions
How long can water be stored in glass jars?
For home-filled emergency drinking water, CDC recommends replacing the water every six months. Store the jars tightly closed in a cool location away from direct sunlight.
Can bacteria grow in a sealed glass jar of water?
Yes. A sealed jar prevents new contamination from entering, but it does not sterilize water that was already contaminated. Start with safe water and a properly cleaned and sanitized container.
Can I store tap water in Mason jars?
Yes. Clean, intact Mason-style jars can hold tap water. For emergency storage, however, CDC favors durable, unbreakable food-grade containers because glass can break.
Should glass water jars be stored in the dark?
Yes. A cool, dark storage location is preferable. Direct sunlight can warm the water and may encourage biological growth when microorganisms and nutrients are present.
Can I freeze water in glass jars?
It is safer not to use glass jars when freezing is likely. Expanding ice can crack or break glass, and leaving extra headspace does not eliminate that risk.
Is rainwater safe to drink after being stored in a glass jar?
Not necessarily. Glass storage does not remove microorganisms, chemicals, metals, or other contaminants that may be present in roof runoff. Drinking-water use requires suitable collection, treatment, maintenance, testing, and compliance with applicable local requirements.
Are reused food jars safe for storing water?
They can be, provided they previously held food, are intact, can be thoroughly cleaned and sanitized, and have a sound lid. Never repurpose containers that previously held pesticides, fuels, cleaners, or other toxic chemicals.
