Ready.gov recommends having an emergency water supply of at least 3 days of water, and they recommend 1 gallon per person, per day for drinking, sanitation, and food preparation. This is the minimum amount of water you should have for your supply; FEMA recommends having a 2 week supply of water. I have an emergency supply of bottled water in my condo, and if you’re like me, you want to know how long your bottled water will last. Below are some general guidelines on how long your bottled water and tapped water will last, and I will go into more detail later in this post.
The shelf life of bottled water will depend on how it was packaged, and where it is stored. To extend the shelf life of bottled water, store it in a cool, dark area. As a general guideline, bottled water will be good for approximately 2 years or more, and bottled tap water will be good to drink for approximately 6 months.
How Long Does Bottled Tap Water Last?
You may decide that you want to store tap water for your emergency supply. I have a couple of 7 gallon containers that I use for water storage when I’m camping, and I find these much easier to empty and refill than plastic bottles of water. The 7 gallon containers do not fit in my kitchen sink, they need to be filled either in my bathtub or outside with a hose.
Bottled tap water lasts about 6 months (if treated with chlorine) before you will need to replace it with new water. Most municipal tap water is treated with chlorine, and chlorine loses it’s potency over time.
I recommend using food-grade water storage containers if you plan on storing your own tap water. If you decide to re-use a storage container for water, FEMA recommends using 2-liter soft drink bottles (they will need to be cleaned and sanitized), and not milk jugs or former fruit juice containers. The reason for this is because milk and fruit sugars are difficult to adequately remove, and create an environment for bacterial growth.
Does bottled Water Go Bad?
I find storing bottled water to be the easiest method of keeping an emergency water supply. If you’re like me, you don’t want to take the time to dispose of all the water in your supply, and buy new water bottles if you don’t have to. I wanted to know how long bottled water will last.
I started researching information regarding the expiration dates, or best buy dates, on bottled water, and couldn’t find anything specific from the FDA’s website regarding this issue (The FDA regulates bottled water, the EPA regulates tap water). In this consumer reports post from 2012, there is an “ask the experts” section where it states:
” The FDA considers bottled water to have an indefinite shelf life if it’s produced in accordance with regulations and remains unopened. So expiration dates on bottles are voluntary and may reflect concerns about taste and odor rather than safety. Bottled water should be stored in a cool location away from direct sunlight, “.
Water does not “go bad” in itself, it needs an outside contaminant (i.e. bacteria, algae, chemicals, etc…) to make it go bad. Some articles state that the plastic bottle may start to break down over time, and leach chemicals into the water. The articles say that plastic leaching into the water does not necessarily make them toxic to drink, but may impact the flavor. You should store your bottled water in a cool, dark place to reduce the risk of this.
FEMA describes commercially bottled water as the “safest and most reliable emergency supply of water“. This PDF from FEMA does not state how long bottled water will stay good, and says to “ Store bottled water in the original sealed container, and observe the expiration or ‘use by’ date“.
According to the information that I found, bottled water may stay good for a lot longer than 2 years if stored in a proper location (cool, dark location) and if they stay sealed. I have read forums where people have drank the water over 5 years after the “best by” date, and they said it tasted fine.
Another reason for the date on the bottle is because water will start to taste different over time due to the bottle breaking down, and the company selling the water can point to the “best by date” if there are complaints about the taste.
I have not been able to find any concrete evidence for how long bottled water will stay good. There are a lot of sites stating something along the lines of “according to the FDA, water has an indefinite shelf life”, but I have not seen any resources directly from the FDA stating this (if you find a resource, please contact me).
If you are concerned that the bottled water is no longer safe to drink, you can treat the water (I will go into treatment options below), but it may be best just to replace your supply every 2 years or so just to be safe. Personally, I plan on keeping my water past the expiration date as long as it looks/tastes/smells fine.
How Many Bottles of Water are in a Gallon?
Well, you know that you are suppose to have at least 1 gallon of water/person/day, and have a minimum of a 3 day supply; so how many bottles of water do you need for your emergency supply?
There are 16.90 ounces (500 ml) in a standard bottle of water, and there are 128 ounces in a gallon. To calculate how many bottles of water are in a gallon, you divide 128 by 16.9. There are 7.57 bottles of water in a gallon.
The table I made below gives you an idea of how many bottles of water you will need for your emergency supply. The package of water that I buy at Walmart hold 40 bottles of water (some only have 24). Divide the numbers in the chart below by how many bottles are in the case of water you buy to know how many cases you will need.
For example, a family of 4 will need approximately 92 bottles of water to have a 3 day supply (1 gallon, per person, per day). If you buy packages of 40 bottles (I buy them at Walmart), you will need 92/40= 2.3 cases of water; so you should buy at least 3 cases of water (since you can’t buy 0.3 cases).
How to Treat questionable water
Hopefully you have a large supply of emergency water and do not need to treat questionable water for consumption. Contaminated water can contain microorganisms (germs, bacteria, viruses) that can cause diseases (i.e. dysentery, typhoid). There are several ways to treat water (Read FEMAs recommendation), but none are perfect. It may be best to use a combination of the treatment methods below.
- Boiling
- Chlorination
- Distillation
- Filtration
Boiling
FEMA describes boiling water as the safest method for treatment. Boiling water will kill almost all pathogens. Bring water to a rolling boil for 1 full minute (at altitudes greater than greater than 6,562 feet, boil water for 3 minutes, according to the CDC).
Boiling water will kill most microorganisms, but will not remove some contaminants, including heavy metals, salt, and most chemicals. Try to remove particles from the water before treatment. If you have a water filter, use it before boiling if needed. If you don’t have a filter, you can strain the water through a paper towel, clean cloth, or coffee filter if you have no other options.
Chlorination/Bleach
If boiling water is not an option, you should consider using a disinfectant on your water supply; you may also want to filter the water as well if available.
You can use household liquid bleach (do not used scented bleaches, colorsafe bleaches or a bleach with any added cleaners) to disinfect your water. This method will kill most microorganisms. Use a liquid bleach that contains 5.25 to 6.0 percent sodium hypochlorite.
This FEMA pdf says you should add 16 drops of bleach per gallon of water, stir the water, and let it sit for 30 minutes. You should be able to smell a light bleach odor from the water, if you don’t, it says to repeat with another 16 drops, stir, and let it stand for another 15 minutes. If you still do not smell a light bleach smell, discard the water.
This “smell test” is not perfect, and you can use a chlorine test strip for you water if you like. According to the EPA, water can have up to 4 parts per million (ppm) of chlorine.
The potency of bleach diminishes over time, so make sure to buy a new bottle of bleach about every 6 months-1 year.
Chlorine will help to reduce pathogens and microorganisms, but the CDC writes that ” contact time, disinfectant concentration, water temperature, water turbidity (cloudiness), water pH, and many other factors can impact the effectiveness of chemical disinfection, “.
Distillation
Distillation will kill most microorganisms and remove other contaminants from the water, including heavy metal, salts, and most chemicals.
This FEMA PDF has an illustration about how to set up a water distiller. Distilling water involves boiling water, and collecting the vapor that condenses back into water. This method seems to be the safest way to treat your water, since it involves boiling the water, and also clears the water of solid objects.
Filtration
Not all water filters are created equal. Water filtration will help remove particles from the water, and will help reduce microorganisms from the water. I recommend using a combination of filtration with boiling water or with a disinfectant (chlorine) on questionable water.
This is what the CDC says about water filtration:”Filtration can be used as a pathogen reduction method against most microorganisms, depending on the pore size of the filter, amount of the contaminant, particle size of the contaminant, and charge of the contaminant particle. Manufacturer’s instructions must be followed. More information on selecting an appropriate water filter can be found at http://www.cdc.gov/parasites/crypto/gen_info/filters.html. Only filters that contain a chemical disinfectant matrix will be effective against some viruses,”.
Conclusion
I hope you found this article helpful. I know that some of you want an exact amount of time that your water will stay good, but this is impossible to provide since not all water is prepared and packaged the same and is not stored in the same environment. If you are worried about your bottled water going bad, I recommend you buy new water, but my non-professional opinion is that bottled water can last for a long time after the expiration date. If anyone finds any additional information that comes directly from the FDA, or FEMA regarding the expiration of water, please contact me. Thanks for reading!