How to Choose a Hydration Pack

Steven hiking uphill in forest with hydration pack

Hydration packs are designed to keep you well-supplied with fluids while hiking, biking, running, or wandering. Hydration packs are available with a wide variety of features.

For our purposes, we’ll organize them into three categories.

hydration reservoirs

Hydration reservoirs are those commonly-used but seldom-seen bladders that we slide into our packs, either as a replacement for – or in addition to – the venerable, old-fashioned bottles in our side pockets.

Reservoirs can hold any liquid you please, although they often adopt the essence of strongly-flavored liquids. Also of note, sugary drinks can encourage bacterial growth in the reservoir or hose. To deal with this, some people put only water in their reservoirs and use bottles exclusively for flavored drinks.

Gregory 3D Hydro water reservoir on wooden surface
  • capacity – reservoirs generally hold 1 to 3 liters of liquid
  • shape – reservoirs can be tall/thin or short/wide
  • construction materials – most modern reservoirs use PBA- and PVC-free plastics
  • bite valve design – the bite valve on the hose influences how easily you can drink. Some bites valves have a lock to prevent leakage and valve covers to protect the mouthpiece from dirt and mud
  • connections – some hoses disconnect from their reservoir
  • opening types – reservoirs display screw lids, zip closes or fold closes. The balance is between having a leakproof seal versus accessibility. A wide opening allows easier cleaning and filling, especially with ice.

Hydration backpacks appear to the eye as just that – a backpack. They have shoulder straps and ride on your back as a typical backpack does.

hydration backpacks

These packs range in their capacity to carry liquids, with the larger packs carrying up to 3 liters.

They also feature storage capacity beyond that of the liquid reservoir. It is in this feature that you’ll see the most variation in hydration backpacks. The space for gear in hydration backpacks can range from as little as 100 cubic inches (1.6 liters) of storage to almost over 2000 cubic inches (36 liters).

Many hydration backpacks have features that you’d expect from a quality backpack:  internal frames, padded waist belts, load lifters and compression straps. Some have integrated rain covers.

There are also hydration backpacks designed for women and younger hikers. These packs may differ from standard packs in that they:

  • are lighter in weight
  • have shorter torso length
  • feature shoulder straps designed for women

hydration waist packs

These are small, low-slung packs which ride at your waist or on your lumbar region (lower back). Some waist packs include hydration reservoirs while others hold 1 or 2 small bottles.

Hydration waist packs vary in their capacity for liquid and other gear but they are generally designed to hold small items like keys, phones and phones. 

Many waist packs are designed as lightweight and sleek to make them compatible with running. Running waist packs also feature easy-to-use bottles and pockets so that runners can access their packs without slowing down.

hydration vests

Hydration vests are not so much packs as they are highly technical garments. They fit closely to your upper body like a vest.

Vests range in their capacity to carry liquids. Some hold a traditional reservoir in a sleeve on the back, while others hold bottles on the front of the vest.

They are the next step for runners who need a lightweight, snug-fitting hydration option without the weight (or space) of a pack. Running vests often offer multiple adjustment points to tighten/loosen the vest, which help eliminate chafing. Some vests offer insulated liners to keep liquids cool as well as ice pockets to cool the runner.

Recognizing that long-distance runners require more support that runners who stay close to home, some hydration vests offer compartments large enough for an extra layer or folding poles. Storage pouches on the straps provide easy access to food, energy bars and gels.


Some hydration backpacks are specialized to serve runners and bikers. They include safety features like:

hydrating in the cold

When you’re out and about on skis or snowshoes, you need to stay hydrated, but cold temperatures provide a unique challenge to your hydration system:  freezing. When ice clogs the bite valve or the hose, you can find yourself in the unenviable position of having a full reservoir but no easy way to drink.

Often your body heat and movement are enough to keep liquids from freezing. However, if you spend enough time outside, you will likely encounter this problem when the mercury drops.

Some cold-weather-ready hydration packs include insulated reservoirs or tubing to help prevent freezing.

the takeaway

Hydration packs are a convenient way to carry the liquids you need while you’re on the move. Hydration packs come in a wide variety, offering options to accommodate hikers, bikers and runners, whether they’re on city streets or backcountry trails.

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Questions? Talk to a gear specialist.