Emergency Water Filters: A Closer Look

Any large-scale disruption reminds us that a solid emergency kit offers peace of mind against the unpredictable. While the coronavirus has not been detected in drinking water supplies, we’ve received many questions about emergency water filters. To help, we’re taking a closer look at  MSR’s lineup, explaining which filters and purifiers are great for your emergency kits. Water treatment is a complicated science, but understanding the basics will help you to pick the one that’s right for you.

At MSR, we’re home to on-site water research lab staffed by treatment scientists and microbiologists. Their expertise provides our team with an incredible level of knowledge for developing water treatment devices. We’ve captured much of their expertise in these articles:

As we all lay low, now is the perfect time to brush up how to stay safe on future adventures, so give those articles a read.

Emergency Water Filters and Purifiers

Filter or purifier?

Before we dive in, it’s important to know the difference between a filter and purifier. A filter (more accurately, a microfilter) is designed to physically remove two types of waterborne microorganisms: bacteria and protozoa. In contrast, a purifier is designed to either kill or physically remove all three waterborne pathogens: bacteria, protozoa and viruses.

Thus, to combat viruses, you need a purifier. Or, you can couple a mircofilter with a purifying agent.


MSR Guardian Purifier

Guardian™ Purifier

Effective against: Viruses, bacteria, protozoa, microplastics, dirt
Flow rate: 2.5 L per minute
Hand pump
Best for:
2-4 people; choosing one device that works for backcountry, international travel and emergency use

Originally developed to keep military service members safe in the field, the Guardian purifier is the world’s most advanced portable purifier. Because it uses hollow fiber technology, it physically strains out contaminants, including viruses. As such, it’s a purifier that’s as easy to use as a traditional microfilter. Built to military specifications, the Guardian’s robust housing withstands challenging environments and the purifier has been tested to NSF Protocol P248, the military standard for microbiological purifiers. In addition, the pump self-cleans, which allows it to handle demanding water types without clogging. Given its speed—2.5 liters per minute—the Guardian is the ultimate tool for doubling as both a backcountry and emergency kit treatment device.

SE200 Chlorine Maker

SE200™ Community Chlorine Maker

Effective against: Viruses, bacteria, giardia cysts
Each batch treats: 200 L (30-minute wait time while chlorine kills microbes)
Creates a batch of chlorine
Best for:
Families and communities, and creating large volumes of drinking water or sanitation solution

A product of MSR’s Global Health efforts, the Community Chlorine Maker provides a fast way to generate chlorine on the spot using just water, salt and electricity. In 5 minutes, it transforms those ingredients into a small batch of chlorine, enough to treat 200 L of water. The chlorine may be used to treat water for drinking, or to create a disinfection solution for sanitizing surfaces and instruments. Sanitation is key during emergencies because microorganisms can spread easily on all kinds of surfaces. The Community Chlorine Maker has been used around the world to support relief agencies and communities in developing nations.

Bottle chlorine has a relatively short shelf life. That’s why the Chlorine Maker is a remarkable tool–it provides chlorine at the push of a button for a variety of safety needs.

MiniWorks Ex

MiniWorks® EX Purifier System

Effective against: Viruses, bacteria, protozoa, microplastics, dirt, chemicals, tastes, odors
Flow rate: 1 liter per minute
Hand pump
Best for:
1-2 people; provides the flexibility to use the purification tablets only when needed

Our best-selling microfilter now comes bundled with Aquatabs purification tablets. This workhorse filter handles demanding water types and is fully field-maintainable. It features a ceramic element for filtering out bacteria, protozoa and particulate, and a carbon element for reducing chemicals and tastes. The Aquatabs tablets add defense against viruses. After filtering the water, simply drop an Aquatabs tablet into the water wait 30 minutes. This combo gives you the flexibility to use the purification tablets only when you need them.

MSR Aquatabs

Aquatabs® Purification Tablets

Effective against: Viruses, bacteria, protozoa
Treatment time: 30-minute wait time while chlorine kills microbes
Chlorine-based tablet
Best for:
1-2 people; adding defense against viruses to any microfilter

Aquatabs purification tablets make great emergency back-up treatment solutions. Ultralight, compact and protected in individual packaging, they’re easy to toss into an emergency kit (or a backpack). Use them after filtering your water in order to combat viruses.

Each year, Aquatabs treat billions of gallons of water, providing a trusted solution for backpackers, relief agencies and defense forces around the world. Given their convenience, there’s no reason you shouldn’t stash a pack away for those “just in case” times.


home emergency water filter

MSR Home Emergency Water Filter Kit

Effective against: Bacteria, protozoa, dirt, microplastics, chemicals, tastes, odors
Flow rate: Depends on spigot
Style: Attaches to standard-threaded home spigots
Best for:
Treating home drinking water if municipal systems are compromised, such as during city boil orders

MSR’s Home Emergency Water Filter Kit offers a convenient way to treat your home drinking water if it’s ever contaminated. For example, if the municipal water treatment system is compromised, the city might issue a boil order. This kit allows you to treat the water flowing from your spigot to make it drinkable. The kit’s adapter threads onto standard outdoor spigots, including those often found on backyard cisterns. The microfilter uses hollow fiber technology to remove bacteria, protozoa and particulate, and activated carbon to reduce chemicals and tastes. To combat viruses, simply add 2 drops of bleach to a gallon of treated water and wait 30 minutes.

The kit is protected in hermetically sealed packaging to ensure it’s ready after long-term storage. Used by the U.S. military for more than a decade, this microfilter provides an alternative to storing weeks’ worth of bottled water as you prepare for unexpected disasters.

We hope this breakdown helps you navigate your options for smart water treatment solutions. Along with everyone, our team is currently laying low, working from our respective home offices. But from afar we hope to remain your resource for information and inspiration—for those future adventures to come!