There are several ways to carry water when you’re out and about.

Hydration Bladders

Hydration bladders, such as the Platypus Big Zip LP, are large pouches that slide into a sleeve inside your backpack’s main compartment. They have a drinking tube which is routed through the top of the pack and is then attached to your shoulder strap for easy access. To drink, all you have to do is put the end of the tube in your mouth. The example given above weighs 170g for the 3 liter size (57g per liter) and costs around $40 ($13.33 per liter). The primary benefit of a hydration bladder is easy of access. Compared to ye olde Nalgene bottles, which could only be accessed by either taking off your pack or asking a friend for help since they were so large they could only fit vertically in your pack’s side pockets, this is a huge improvement. They also typically have larger openings which makes them easier to fill.

Unfortunately hydration bladders have a number of drawbacks:

  • They’re relatively heavy and pricey compared to other options.
  • They’re invisible: without opening up your pack and pulling out the bladder it’s very difficult to judge how much water you have left. This is an important part of deciding whether you should stop and filter as you pass a water source.
  • They’re a pain to get in and out of your pack when refilling, especially if your pack is very full.
  • They’re not compatible with electrolyte or energy supplements (such as Nuun tablets or Tailwind endurance fuel) because the sugars will coat the inside of the pouch and tube, promoting mold growth.
  • They’re hard to clean.
  • They’re not redundant. Few people who use bladders carry a second container for water.

Out of that list, I’d say the hassle of water filtration (pulling the pouch out, disconnecting the tube, filling it with water, reconnecting the tube, and shoving it back in while hoping that the tube doesn’t get kinked as you do so) is the biggest negative. Because filtration becomes such a chore you’re reluctant to do it which means you want a bigger bladder so that you have to stop and filter as little as possible. You can get away without filtering entirely on day hikes but any overnight is going to require it, and carrying a ton of extra water just to avoid filtering is a huge weight penalty.

After having used bladders for years I do not recommend them.

Soft Bottles

Next up: soft bottles, such as the Platy Bottle (2 liters, 40g or 20g per liter, $12.95 or $6.48 per liter) or Evernew Water Carry 2L (2 liters, 42g or 21g per liter, $12.82 or $6.41 per liter). These are soft-sided collapsible plastic bottles (glorified pouches with screw-on caps, really) that you drink out of directly as opposed to through a tube. Since they require physical access they’re stored in your pack’s side pockets.

Compared to hydration bladders they’re about a third of the weight per liter and about half the cost as well. They also make it easy to see how much water you have left. However, they have the following drawbacks:

  • Since they’re not hard-sided they don’t hold their shape as they become less full, which makes them more and more difficult to put back into your side pockets.
  • They typically have small openings which makes them harder to fill.
  • Some models feature untethered caps which are easy to lose since you must always remove the cap to drink from them.

I don’t recommend soft bottles. I find them too frustrating to reinsert into side pockets one-handed and there are better ways to carry extra water inside your pack.

SmartWater Bottles

SmartWater bottles are available in a variety of sizes from any gas station, convenience store, or supermarket. Let’s do a pros list:

  • They’re inexpensive and light. The one-liter variety costs $1.50 and weighs 40g, a quarter of the price-per-liter of soft bottles but twice the weight-per-liter.
  • Compared to many other water bottles they’re light and long and uniformly narrow, and since they’re hard-sided they’re easy to reinsert into your pack’s side pockets regardless of how full or empty they are.
  • Since they’re hard-sided they still allow air to circulate when empty, which makes them more suitable for electrolyte mixes and supplements since they can easily be dried out.
  • They’re clear so you can see exactly how much water you have left.
  • They come in a sport (flip-top) cap variety which means that you don’t have to remove the cap to drink from them (although you must still remove it to fill them up).
  • They’re surprisingly durable. People have reported hiking thousands of miles and finishing with the same bottles they started out with.
  • Redundancy: you can carry a water bottle in each side pocket.

The only drawback I can think of is that since they’re hard-sided they always take up the same amount of space even when empty.

SmartWater bottles became popular in the outdoors after it was discovered that their threading was compatible with the Sawyer Squeeze, the most popular method of water filtration. This means you can attach the Squeeze directly to the bottle, allowing you to filter directly into it or drink through the filter, cleansing the water as you do so.

Water Containers

The CNOC Vecto is in a category of its own. A two liter soft bottle with a Sawyer-compatible threaded cap on one end and a large slide-shut opening on the other, it can be combined with a Sawyer Squeeze and a SmartWater bottle to create a gravity filter, one of the most convenient water filtration setups. And at $14.99 ($7.50 per liter) and 78g (39g per liter) it’s competitive with soft bottles as additional storage capacity.

Recommendation

I’ve been using a pair of 700mL sport cap SmartWater bottles for a couple years now and I’ve never been happier with my water carrying setup. I use the smaller size because I find that these fit more securely into the side pockets of my pack (an Osprey Levity 60 as of this writing, an Osprey Exos 58 before that).

I also carry a CNOC Vecto, both to use as part of the aforementioned gravity filter setup as well as additional water capacity, bringing my maximum carry up to 3.4 liters.