How to Choose a Water Filter or Purifier for the Backcountry

(By Kate Sedrowski)

When you’re exploring the backcountry while backpacking or hiking, you need to stay hydrated. But water is heavy, so on longer trips, you definitely can’t carry all that you need with you from the start. Instead, you have to bring something to make the water sources along the trail safe to drink. But do you need a water filter or a water purifier – and which of the many options is the best choice?

The Difference Between Filtering and Purifying Water

Before you choose a water treatment option, it’s important to understand the difference between filtering and purifying water. When you filter water, a physical barrier stops sediment, bacteria, and protozoa from passing through, so those microorganisms don’t end up in the water you drink. However, most water filters don’t prevent viruses from passing through because the holes in the filters are 0.2 microns in size, and viruses are smaller than that.

Purifying water is different because instead of a physical barrier, purification uses either chemical treatments or technology such as UV light to kill bacteria, viruses, and other organisms. This makes purified water cleaner and safer to drink, even though it sometimes looks dirtier since it still has sediment in it.

Types of Water Purifiers & Filters

Choosing between the many options of water purifiers and filters can be overwhelming. Let’s break down the various types of filters and purifiers, along with their pros and cons.

UV Purifiers

One of the best ways to purify your water is with UV light. These types of purifiers come in the form of a water bottle cap (like the CrazyCap) or a pen (like the SteriPen). You simply press a button to turn on a cycle of the UV light which kills microorganisms in the water.

CrazyCap uses an integrated deep UV-C light which actually enters the cells of bacteria, viruses, and protozoa to kill them by destroying the nuclei. Used in CrazyMode, CrazyCap will kill 99.9996% of viruses and bacteria, and your water will be ready to drink in just two minutes.

UV purifiers do need to be charged in order to function. CrazyCap will last for about a week in the backcountry on one charge, and you can recharge it via the USB cable with any portable charger that you bring on your backpacking trip.

Chemical Purifiers

Chemical purifiers consist of chemicals you add to your water in order to kill viruses and bacteria. These usually come in the form of tablets or drops. Common chemical purifiers include Aquamira, which contains chlorine, and Potable Aqua, which is a type of iodine purifier. You can combine chemical purifiers with water filters in order to get the benefits of both filtering and purifying.

But a big downside to chemical water purifiers is that they take a lot of time to work – usually at least 30 minutes. Plus, some of them, especially iodine, tend to add a weird taste to your water. Often, people bring a chemical purifier as an emergency backup in the backcountry instead of using it as their main water purifying choice.

Gravity Purifiers/Filters

Just like the name implies, gravity purifiers let gravity do the work of filtering the water. To do this, you hang a bag of dirty water which then drips down through a filter or physical purifier and then the clean water collects in a reservoir.

Gravity purifiers are an excellent choice for groups, since they can easily treat a lot of water. However, they are fairly slow, and they require something sturdy enough to hang the water from, which might not be easy to find in some backcountry landscapes, like the desert.

Pump Filters

The pump filter is a classic in a backpacking pack, because it’s generally small, lightweight, and fairly easy to use. As you might expect, a pump filter requires manual labor to actually pump the water, so you can’t just set it and forget it while it does it’s job like other options, such as UV light or gravity purifiers.

With a pump filter, you stick a hose into your water source, then pump the water through another hose into your water container. Some benefits of pumps are that you can utilize shallow water sources, and you can pump as much water as you need. But pumps can clog, and once again, you have to keep pumping if you need more water.

Bottle Filters

Water bottle filters are easy to use, with a physical filter integrated in the bottle to remove sediment and bacteria. But with just a filter, these don’t purify the water or kill viruses.

Bottle filters are handy since you can drink straight from them, but you are also limited in the volume of water you can filter. Also, the filter will usually eventually get clogged and have to be cleaned before it can be used properly again.

Squeeze Filters

Squeeze filters are kind of a combination of pump and bottle filters. You squeeze the water through a physical filter which is attached to a flexible bottle. You can drink the water directly or squeeze it into another container.

While these are easy to use, they require maintenance to keep the filter clean and water flowing, and, of course, they don’t kill viruses.

Straw Filters

These filters allow you to drink directly from a water source. You simply put one end of the straw into the water and suck the water through the other end. A big downside to straw filters is that you can’t filter water to bring with you along the trail – you have to be at the water source to drink.

An Alternate Water Treatment Option


While it usually isn’t the best choice as your main option, remember that boiling water can be a good backup water treatment in an emergency. You’ll obviously need a backpacking stove of some kind, as well as enough fuel.

Boiling water will kill bacteria and viruses after one minute, except at high altitude. If you’re over 6,500 feet (2,000 meters), you need to boil your water for three minutes to be effective.

Now that you understand the different types of water filters and purifiers, you can choose the right one for you and hit the trail safely! For a UV light purifier, check out all the great CrazyCap options!

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