How to Choose a Portable Water Purifier

There are many ways to filter your water, but the best setups require minimal effort and instructions. The easiest options include straw-style filters and bottles that use gravity to remove bacteria, giardia and cryptosporidium.


Another easy option is GRAYL’s Geopress, which works a little like a coffee press: simply fill and press. It eliminates viruses, too.


Pumps are a great way to filter water and can be used with hydration bladders, hoses that connect directly to a source, or as stand-alone filters. They can require a bit more hand-squeezing than gravity models and are also susceptible to freezing (but aren’t as much as you might think). Most pumps have a maximum output per pump that’s dictated by efficiency, so it’s important to choose a model that meets your needs.

Most models have a head (in feet) performance curve that shows capacity at different throttle positions. This is important to understand since the power required will change at different throttle settings. Typically, the higher the head, the more efficient the pump is at a given flow rate.

A strainer should be attached to the inlet hose of the pump to prevent large debris from damaging the pump. The inlet hose should then be connected to a source of clean water, such as a river, creek, or lake. The hose should be placed in the source, and then the outlet hose should be connected to the pump. As the pump is pumped, the water will move from the inlet through the strainer and then out the outlet. The filtered water will then be stored in the tank. Some pump models also come with a depth gauge, which is helpful when filling up from shallow sources.

Gravity Filters

Gravity filters use the force of gravity to turn raw water into clean drinking water. They consist of a reservoir to hold the contaminated water, and a tank or bag to store the clean water. The dirtiest water is poured into the reservoir first, and the cleaner water flows down into the filter. This process removes contaminants that can cause illness or make the water taste bad.

A few of our favorite options include the Platypus GravityWorks system and the MSR Guardian gravity purifier. Both systems have a high flow rate and can treat large volumes of water. They’re also the easiest to use, with no extra parts or steps to follow. However, they can still be difficult to maintain, especially if the filter becomes fully clogged. In these cases, it is important to backflush the system and/or replace the filter.

Another good option is the SteriPen Ultra, which uses UV rays to destroy bacteria, protozoa, and viruses in your water. It can be a little more difficult to maintain than a pump or gravity filter, but it’s one of the fastest and most convenient ways to get clean drinking water in an emergency.

Straws & Bottles

Drinking straws are one of the biggest contributors to plastic marine waste and they’re a major no-no for those seeking to minimize their impact on the environment. The thin plastic straws break down into microplastics that are ingested by wildlife and that pollute the ocean and waterways, including our own homes. Plastic straws are also a huge liability if you’re backpacking and relying on an unfiltered water source.

For an easy-to-use alternative to a full-blown backpacking water filter, we recommend checking out reusable straws or a filtered bottle with a straw lid. A straw-based system like the LifeStraw Peak Squeeze or Sawyer Squeeze offers a barebones solution that requires no extra parts and only relies on your suction and squeezing to power the filtration process. These systems are typically made with either a collapsible or soft bottle and feature a high-flow microfilter, fueled by your guzzling force.

You can find straw-based reusable bottles in a variety of lengths, thicknesses, and materials. Some options are eco-friendly and biodegradable, such as bamboo reusable straws, which are an excellent choice for anyone looking to minimize their impact on the environment. Others are more durable and hygienic, such as the Grayl GeoPress Water Filter and Purifier. This sleek all-in-one solution is designed with travel and light adventuring in mind, requiring no pumping, battery use, or chemicals.

UV Filters

UV filters use a germicidal wavelength of light to deactivate living microorganisms in water. They’re effective against bacteria, viruses and protozoa, but not toxins or heavy metals. Unlike chemical treatments, they don’t add taste or smell to the water. However, they require electricity for operation and do not remove other types of contamination.

The best portable UV water purifiers are small and lightweight. Some models are separate devices that you place into a water bottle, while others combine the container and lamp into one unit. They’re simple to operate: just turn them on and wait a few minutes for the treated water to be safe to drink.

These systems are generally more expensive than other types of water treatment devices, but they provide peace of mind on backcountry hikes. To maximize the value of a UV system, look for models that incorporate a flow meter to keep water flowing at a constant rate. This helps maintain the pump filter’s performance and reduces cleaning chores and field maintenance needs.

Before backpacking or hiking in a new location, research local water quality and learn how to treat the water you’ll be using. The National Park Service and local guiding services can be good places to start, but you can also contact your state’s health department or environmental agency for information about specific areas.