LifeStraw Peak Gravity 3L Review

The LifeStraw Peak Gravity is one of the most versatile and durable gravity-fed systems we tested. Simply interchange the microfilter with the LifeStraw Peak Squeeze bottle or place the filter directly into the stream and suck water through as a straw. Our only complaint about this system is the small opening on the storage bag, which can be difficult to fill in shallow water. That aside, an easy setup and a minimalist design will have you filtering water in less than one minute, and a filter life of 500 gallons will keep you hydrated for many adventures to come.

Performance Comparison

Water Quality

While the Peak Gravity uses a 0.2-micron hollow-core membrane that protects against 99.999999% of bacteria, 99.999% of parasites, and 99.999% of microplastics, silt, sand, and cloudiness, it is not effective against viruses, heavy metals, or chemicals. During our testing period, we were impressed by the overall water quality, which was clear and did not have any lingering aftertaste, even when filtering in turbid water after a few days of thunderstorms.

Durability and Maintenance

This metric is perhaps where the Peak Gravity really shines. Constructed from BPA-free, premium materials, and a fully leakproof storage bag, this gravity filter is designed with longevity in mind. Maintenance is easy thanks to the included backwash syringe — simply remove the filter from the storage bag, attach the backflush syringe and submerge it in fresh water while using the syringe to draw water up and down the other side of the filter. After many uses in the field, our testers found that the flow rate would increase after a little maintenance. You know your filter has reached the end of its life if water no longer flows through, even after performing the backwash procedure.

Regarding storage, LifeStraw recommends for storing your filter in a saline solution comprised of one teaspoon of salt in purified water. This will keep the filter from getting drying out and also help retain the hydrophilic properties of the membrane.

Treatment Time

While the Peak Gravity 3L did not offer the fastest nor the most competitive flow rate, one liter per 30-34 seconds ain't bad. However, other comparable gravity filters offer double the flow rate, which may be important to larger groups and base camps.

Weight and Packability

This is one of the lightest and most packable gravity filtration systems we tested. The dimensions of this filter are 8.6 x 20.8 inches, with a hose length of 47 inches. Weighing only 8.1 ounces and packing down to the size of a Nalgene bottle, you won't think twice about bringing this filter along for your next backcountry base camp.

Ease of Setup

An intuitive setup helped the Peak Gravity receive high marks here. The filter comes with only seven parts, which include the storage bag, the hose, a quick connector to attach the filter, a cap that allows for storage, the backwash syringe accessory, and a carabiner and carry strap. The setup and minimalist design took our testers less than 30 seconds to assemble and get ready to filter.

Ease of Filtration

Unfortunately, we couldn't give the Peak 3L high marks in this metric due to the small opening on the storage bag, which was difficult to fill in shallow water. We had to get creative to fill the bag in shallow streams, while it was much easier to fill when submerged in deeper pools.

Perhaps one of the most notable features of the Lifestraw Peak Series is its versatility. This filter can be used as a gravity system, a straw used to drink directly out of the stream, or attached to the LifeStraw Squeeze bottle.

Should You Buy the LifeStraw Peak Gravity 3L?

If you're looking for a gravity-fed water filter that offers a sleek and durable design, a long-lasting microfilter, and an easy-to-use, easy-to-maintain setup, the Peak Gravity 3L won't let you down. We love that this filter has interchangeable parts, compatible with other Peak Series components. Available for a fraction of the cost of its gravity-fed competitors, the only drawbacks we found with this filter were the small opening utilized to collect water and the slightly slower flow rate.

What Other Backpacking Water Filters Should You Consider?

If you're interested in other gravity-fed water filters that offer a faster flow rate in exchange for a little more investment, check out the top-rated Platypus GravityWorks and the Katadyn Gravity BeFree 6L.