Your water bottle is your link to life and how to choose water bottles becomes very important depending the length and the type of trip you expect to take. There are numerous types and shapes to consider and the correct water bottle is the one that will perform during your trip conditions. Water bottles are either rigid or collapsible and each has its own features and advantages. Collapsible water bottles take up less space when they are empty.
How Much Water Do You Need?
The size and shape of the water bottle is directly related to the amount of water you need each day and how much water you need in case you can't refill it for a period of time. Keep in mind that your water weighs approximately 8 pounds per gallon. Backpacking needs are quite different from kayaking needs. You will be able to carry more water weight during kayaking versus backpacking. Also take into consideration if you will be using a hydration pack along with the water bottles.
Storing Water Bottles:
If you are backpacking, will you be storing water along the way (and hiding the water bottles) for the return trip. If you are, you will be needing additional water bottles and the sizes of the water bottles will be dependant on the amount of water you will be needing to store.
Flexible Water Bottles:
Flexible water bottles that roll up to save space are used quite often while kayaking. The flexible water bottles fit very easily into small spaces in the kayak hatches. I usually am very cautious and place the filled flexible water bottles into a dry sack in case the water leaks or the bag breaks. I don't want the hatch filling up with water and potentially wet everything in the hatch even though most of the items are in dry bags, too. If you decide to use flexible water bottles while hiking, be aware that the bottles are harder to handle when you need some water and when the water fills the bag only half way.
The shapes available are round or square and each have advantages depending on the use of the bottles. The round bottles fits into pockets on your backpack while the square bottles take up less space in your backpack.
If you have a specific water filter, make sure that the bottles will connect directly to your water filter. If you haven't purchases a water filter yet, purchase the water filter first before selecting water bottles.
Polycarbonate: These bottles are the most expensive bottles and they won't retain orders or flavors. They are more durable and won't taste like plastic. The bottles are usually clear.
Polyethylene: These bottles are inexpensive and might taste like plastic and retain odors. They will not crack easily.
Size Of The Bottle Mouth:
Depending on the type of hiking you do (day or overnight), the large mouth bottles can accommodate ice cubes (obviously not a factor during overnight hiking). Depending on the type of cooking you do, the smaller mouth bottles are easier to pour than the large mouth bottles. Little items that your need can be placed in large mouth bottles (if you don't need the bottles for water).