Frequently asked questions about care and use, cleaning, maintenance and warranty for GRAYL. Also health and safety about filtered and purified water.

Care & Use

How do I separate the INNER PRESS from the OUTER [RE]FILL?

Place one hand on the OUTER [RE]FILL and another on the INNER PRESS then rotate while pulling apart.

Tip – Using a twisting motion helps facilitate separation. When your GRAYL is completely dry, the INNER and OUTER parts may require more force to separate. Make sure to twist as you pull apart.

How do I filter water with a GRAYL?

Fill the OUTER [RE]FILL at selected source. Make sure NOT to fill past the indicated fill line. Utilizing your body weight for mechanical advantage, press with steady downward force. Press on the ground, or below 20 inches. Drink Freely™.

Tip – Before applying steady downward pressure, ensure the lid is removed and avoid "cupping" the palm of your hands over the top of the INNER PRESS. This allows air pressure to release during the filtration process.

How do I remove and/or install a filter?

Removal. Locate filter lock tab at bottom of INNER PRESS. Pull out filter lock tab (with index finger) and twist filter clockwise.

Installation. Insert filter into INNER PRESS and rotate counterclockwise. Screw filter until filter lock tab clicks into filter lock slot. Do not over tighten.

Before first use. Before drinking, press water through the system twice. Discolored water (caused by harmless activated carbon dust) is normal during the first few cycles.

Why do you recommend "pressing" either on the ground or on a flat surface below 20"?

Mechanical advantage, baby. No big muscles required. We always recommend pressing with steady downward force at a lower height (either on the ground or a level surface no more than 20 inches) so you can leverage your body weight for mechanical advantage. It's the fastest, most efficient, and easiest way to purify water on-the-go. If you want to test this technique, try from a lower surface and a higher surface (you'll feel the difference).

How long does a purifier cartridge last?

The lifespan of the filter or purifier is dependent on the quality of your water source. High levels of sediment in the water will shorten the life span of the filter. For best results, change the filter after 300 cycles (40 gal / 150 L). Use beyond filter capacity diminishes filtration effectiveness and may result in drinking unsafe water. If water flow rate is noticeably slower than usual then the filter should be replaced.

What is the shelf life of my Purifier Cartridge?

Between uses, if you care for them properly, your Purifier cartridges will last up to three years after first use. The one part of the technology that will degrade is the Activated Carbon (AC)- which filters heavy metals and chemicals. AC absorbs impurities from the air, so it naturally degrades over time once unwrapped. You can limit this effect by drying thoroughly, then placing it into an airtight bag. Our cartridges are interchangeable, so after travelling with the Purifier installed, you can install Tap Filter for daily use (for potable water only) and store the Purifier until your next trip.

Can I use the Purifier cartridge to filter liquids other than water?


Does the Purifier cartridge make sea water safe to drink?

No. Salt water contains ions like magnesium and sodium that our filters are not effective against. To remove salt from ocean water, you need a desalinization filter.

Can I put any GRAYL components in the microwave or freezer?


What should I do if my GRAYL freezes?

If your GRAYL freezes once, it is fine to continue using. But if it happens more than once, install a new filter cartridge.

GRAYL conducted freeze/thaw tests in an independent lab to determine the effect of freezing your GRAYL. After a single freeze, the Purifier Cartridge maintained performance after a single freeze/thaw cycle.

However, after three freeze/thaw cycles, the Purifier Cartridge suffered a drop in performance below acceptable levels. For safety, we recommend changing the Purifier Cartridge after two freeze/thaw cycles.

Is the GRAYL dishwasher safe?

The OUTER [RE]FILL, INNER PRESS, and CAP are top rack dishwasher safe; otherwise wash by hand with warm, soapy water. Wash these parts before first use. Rinse cartridge only, no soap.

Note: do not place purifier cartridges in the dishwasher or in soapy water.

Can I use soap on a filter?

Do not wash purifier cartridges with soap or other cleaning agents. You may rinse the cartrdige with clean water as needed.


Are all GRAYL components BPA-free?

Yes, all GRAYL components are BPA-free. We only use BPA-free food-grade plastics such as Polypropylene #5 and ABS.

Isn't tap water good enough?

Maybe. Throughout the USA, Canada and Europe, tap water is generally safe. High levels of chlorine kill pathogens (germs) so you don't get sick. But the USA EPA allows drinking water to contain trace amounts of a wide range of impurities - certain heavy metals (lead, arsenic, iron), industrial and pharmaceutical chemicals, elements you can taste (chlorine, copper). The activated carbon used in GRAYL® filters has been proven to greatly reduce many of these contaminants. The result: great tasting water and one less thing to worry about.

What type of filter media is used in Purifier cartridges?

The Tap Filter uses activated carbon fiber with an extremely small micro pore structure and a capacity for absorption far greater than conventional granular activated carbon.

The Purifier Cartridge uses a patented G3+™ Filtration Media– three filtration technologies in one for added protection: 1) A triple-charged mesh traps disease-causing germs while allowing water to flow quickly, 2) Activated natural carbon (made from coconut shells) attracts and traps many heavy metals, industrial chemicals, 3) An integrated anti-microbial agent suppresses the growth of mold, mildew and bacteria, keeping GRAYL fresh between uses.

What is the pore size (microns) of the Purifier Cartridge (and Trail Filter)?

Pore size is not relevant to G3+™ technology; it's like asking how much horsepower a laptop computer has. Pore size is relevant in 'mechanical filters', which work by forcing water through tiny pores in a filter. In a mechanical filter, the biggest pore must be smaller than the smallest germ. The downside of mechanical filters is that tiny pores prevent rapid flow of water, so they work slowly or require lots of pressure. Instead, G3+™ technology uses electroadsorption; relatively large pores overlaid with a positively-charged mesh (think: little magnets) that latch onto germs. The result is fast-flowing, clean water so you can #PurifyWaterAnywhere.

What is activated carbon?

Activated carbon absorbs waterborne impurities. Carbon has been used for thousands of years - the ancient Phoenicians (1200 BC) stored water in charred barrels for long sea voyages. Carbon is "activated" with heat and oxygen to create tiny pores, which increases the surface area. GRAYL's G3+™ Filtration Media (used in the Purifier Cartridge and Trail Filter) incorporates ultra-powdered activated carbon throughout the filter, creating an even higher surface area than in most filters. The carbon is made from natural coconut husks. Activated carbon's high surface area adsorbs a wide range of impurities commonly found in tap water, including various metals, organic molecules and industrial and pharmaceutical chemicals.

Is the filtered water from GRAYL safe for drinking in the developing world?

Yes, but use the Purifier Cartridge, GRAYL's best protection against the full-spectrum of waterborne pathogens that cause human disease (viruses, protozoa and bacteria)). Of course, we always recommend filtering the cleanest possible water you can find.

Warranty & Return Policy

What is GRAYL’s warranty?

Every GRAYL is accompanied by a ten (10) year warranty covering workmanship and materials. For replacement information please contact us at: www.thegrayl.com/contact-us

What is GRAYL’s return policy?

Items can be returned within 30 days of the date of receipt. They must be in new, unused condition. For this reason, we encourage customers to give the system a dry run (without water) to understand operation and each of the different components. Shipping charges are non-refundable. In the event of a return or if a package isn't deliverable by a carrier - only the cost of the merchandise is eligible for a refund. Please contact us with any questions about our policy or to initiate a return: info@thegrayl.com


Why is GRAYL based in Seattle?

We love Seattle. We live on the shores of the mighty Puget Sound. How mighty? We have our own killer whales and can see snow-covered mountains to the North, South, East and West. We bike to work, walk to lunch and on epic snow days we sometimes shut the doors in favor of carving turns in the Cascades. Seattle is a great place to live and GRAYL is a great place to work.