An UltraPress cartridge is rated for ~300 cycles (150 liters / 40 gallons); GeoPress cartridge for ~350 (250 liters / 65 gallons). The effective lifespan of a cartridge varies depending on the quality of the water sources—the clearer, the better. High levels of silt or sediment will shorten the lifespan of a cartridge. To maximize the effective lifespan of your cartridge always choose the clearest water available. If necessary, pre-filter the water using a handkerchief or t-shirt as you fill the Outer Refill.

As you use your Grayl purifier, the ‘press time’ will slowly increase with use. When ‘press time’ reaches ~25 seconds (or three years have elapsed since first use), it is time to replace your cartridge. Note: Especially cold water may take longer to press and does not indicate your cartridge needs to be replaced.

Stored under proper conditions, an unused (and airtight) cartridge has a shelf life of 10-years. Once a cartridge has been opened, it may be used for up to 3-years or until press time reaches ~25 seconds, indicating it is time to replace the cartridge.

Grayl cartridges can filter and purify virtually any freshwater source. The cartridges cannot desalinate water, so stay away from salty or brackish water. When purifying freshwater, always begin with the cleanest (least silty) water available. For instance, streams and rivers are generally better than lakes and bogs, which often have higher levels of sediment and tannins. Grayl cartridges are designed to remove low levels of chemicals and heavy metals but are NOT designed to protect against industrial disasters, coal ash spills, very high lead levels, mercury, nuclear disasters, high tannin concentration or water that contains toxic blue-green algae (cyanobacteria). In these conditions, it’s important to find another water source.

Grayl products use electroadsorptive media to capture pathogens and inorganic contaminants as dirty water is pressed through the cartridge. As water passes through the purifier media in the cartridge, waterborne pathogens (99.99% of virus, 99.9999% of bacteria, and 99.9% of protozoan cysts, including Rotavirus, Hepatitis A, Norovirus, Giardiasis, Cryptosporidium, E. Coli, Cholera, Salmonella, Dysentery) permanently bind to the media and activated carbon absorbs chemicals, heavy metals, and eliminates bad tastes and smells. After the press, water is ready to chug, sip or store for later.  

Thanks to the Spout Cap, it is easy to avoid cross contamination from the environment or untreated water. However, if dirty water does come into contact with the Inner Press, disassemble and wash the Grayl (not the cartridge) with soapy water and rinse thoroughly. Alternatively, thoroughly dilute potential contaminants by pressing and agitating water through the Grayl Purifier 5-7 times.

Before putting your Grayl away after an adventure, dry out the cartridge to prevent growth of mildew and odors. Thoroughly dry the cartridge by performing one ‘dry press’ by pressing the wet purifier into an empty (no water) Outer Refill and dumping excess water. Allow the cartridge to air-dry thoroughly (depending on humidity it will take 2-4 days to completely dry). Hand wash all other parts with warm, soapy water. For long-term storage, reassemble the unit to create an airtight seal for storage. Cartridges can last up to three years after opening if cared for properly between uses.

es, you may add electrolytes, drink mixes and other flavorings into your GeoPress® when it is equipped with a New! GeoPress® Cartridge (V2) and a One-Way Electrolyte & Drink-Mix Valve.

For bottles equipped with a cartridge sold pre-April 2023, we do not recommend adding flavoring or electrolytes directly into your GeoPress® because it can decrease the lifespan and efficacy of your cartridge. Instead, we recommend you pour your clean drinking water from your Grayl into another water vessel containing electrolytes or flavorings. Alternatively, upgrade to a GeoPress® Cartridge (V2) and add a One-Way Valve.

Both the UltraPress and the GeoPress offer the highest level of protection from waterborne pathogens (99.99% of virus, 99.9999% of bacteria, and 99.9% of protozoan cysts, including Rotavirus, Hepatitis A, Norovirus, Giardiasis, Cryptosporidium, E. Coli, Cholera, Salmonella, Dysentery) as well as many heavy metals, chemicals, and microplastics.

The GeoPress filters and purifies 24 ounces of water with each press and is the best option for groups and individuals looking for a higher capacity option.

The UltraPress filters and purifies 16.9 ounces with each press. The compact design is ideal for individuals looking to maximize space as the bottle fits in most backpack side pockets, bike water bottle cages, and cup holders.

Grayl products are made from: BPA-free polypropylene #5, food-grade silicone & ABS thermoplastic polymer. Purifiers are designed in Seattle, Washington, the purification media is produced in the United States and the bottle components by our manufacturing partners in China.