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At a campsite at dusk, the lake holds the water and a filter makes it drinkable. Gravity vs squeeze water filter is the choice: a gravity bag hangs and filters water on its own, and a squeeze bottle filters water when you squeeze it. A gravity filter suits a camp that needs water for a group, and a squeeze filter suits a hiker who needs a drink on the move.
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Gravity vs squeeze water filter: the quick answer
Pick a gravity filter when the water is for a camp and the bag can hang while the water filters. Pick a squeeze filter when the water is for a hiker on the move and the bottle is in hand. A gravity filter needs a place to hang the bag and time for the water to flow through the filter. A squeeze filter needs a hand to squeeze the bottle and a cup or bottle to catch the water. The gravity filters in this guide are bag systems that hang from a tree, a hook or a pole.
Gravity filters: how they work
A gravity filter is a bag and a filter straw. Fill the bag with water from a lake, a river or a creek, hang the bag from a tree, a hook or a pole, attach the filter to the bag, and gravity pulls the water through the filter. The bag hangs and the water filters on its own, with no pumping or squeezing and no electricity. The filter straw has a hollow fiber membrane that reduces sediment and improves taste and odor, with activated carbon and pre-filters for multi-stage filtration. Open the drainage valve first to empty air from the hose before connecting the straw, or the bag can sit in a vacuum state with no water flow. After use, rinse with clean water and hang the bag upside down to dry.
Squeeze filters: how they work
A squeeze filter is a soft bottle or bag with a filter in the cap. Fill the bottle with water, then squeeze the bottle to push the water through the filter and into a cup or a bottle. The filter works when you squeeze it, and it stops when you stop squeezing. A squeeze filter is light and small, and it fits in a pack for a hiker who drinks on the move. It filters water a drink at a time, so it suits a hiker, not a camp that needs water for a group. The gravity filters in this guide are bag systems, not squeeze bottles, so the gear here is for the gravity side of the choice.
Gravity vs squeeze: the table
| Style | How it filters | Best for |
|---|---|---|
| Gravity | Hang a bag; water flows through the filter on its own | A camp that needs water for a group |
| Squeeze | Squeeze a bottle; water flows when you squeeze it | A hiker who drinks on the move |
The gravity filters in this guide
Membrane Solutions 1 Gal Gravity Water Filter is the top gravity filter here. It is a 1-gallon gravity water filter system with a 0.1-micron 4-stage filter, certified to NSF/ANSI 42, 372 and 401, and it filters up to 1,320 gallons at up to 500 ml/min. It weighs 0.7 lb, less than the LONVEAR at 1.5 lb, and it measures 3.9 by 2.3 by 9.0 inches. The adjustable tree strap fits trunks from 22.5 to 41.5 inches. It is backflushable and connects to standard water bottles with no syringe needed, and it meets FDA, food-grade and BPA-free standards.
Waterdrop Gravity Water Filter Straw is the next gravity filter here. It is a 0.1-micron filter straw with a 1.5-gallon gravity-fed water bag, and it filters up to 1,400 gallons at up to 700 ml/min. That flow is more than the Membrane at 500 ml/min and the LONVEAR at 300 ml/min. The bag holds up to 1.5 gallons at a time, about 11 bottles of 500 ml. The straw has a backwash purifier function, and the mouthpiece comes off for a flush with clean water. A pop bottle with a thread diameter of 27.5mm fills with clean water for backwashing. The maker gives a 30-day limited filter warranty.
LONVEAR 1 Gallon Water Filter Bag is a 1-gallon gravity filter bag with a 0.1-micron 4-stage filter straw. It meets NSF/ANSI 42, 372 and 401 standards, and it filters up to 1,057 gallons at up to 300 ml/min. The bag is food-grade TPU, BPA-free, wear-resistant and odorless, and it holds up to 1 gallon at a time, about 8 bottles of 500 ml. It weighs 1.5 lb and measures 7.8 by 2.0 by 15.7 inches. An adjustable strap lets the bag hang from trees, hooks or poles.
Purewell 3-Stage Gravity Water Filter System is a countertop gravity filter system, not a bag for the trail. It is a 304 stainless steel countertop system with 2 filters and a stand, and it uses a 0.01-micron hollow fiber UF membrane, finer than the 0.1 micron of the bag filters. It is certified to NSF/ANSI 42 and 372, and it reduces 99% of chlorine and filters 99.99% of tiny materials from the water. The system keeps a flow rate of 4 gallons per hour. The system holds 2.25 gallons, and the 2 filters provide up to 6000 gallons, with each filter element lasting 3000 gallons. The maker says to replace the filter elements every 6 months. It needs no electricity: the upper chamber holds unfiltered tap water and the lower chamber holds clean water after filtering. The filter element does not lower TDS value.
How to pick a gravity filter
Match the filter to the trip. A 1-gallon bag suits a solo hiker or a small group, and a 1.5-gallon bag suits a camp that needs more water at a time. A 0.1-micron filter is the pore size of the bag filters here, and the Purewell at 0.01 micron is finer. A filter certified to NSF/ANSI 42, 372 and 401 has an independent check on the standards it meets. A backflushable straw keeps the flow up: the Membrane and the Waterdrop backwash with clean water. A strap that adjusts from 22.5 to 41.5 inches hangs the bag from a tree at camp. A warranty helps: the Waterdrop gives a 30-day limited filter warranty. For a camp filter, see the best water filter for camping guide. A filter is not the only way to treat water: purification tablets are another option for a hiker.
FAQ: power away from the grid
What is the difference between a gravity and a squeeze water filter?
A gravity filter hangs a bag and filters water on its own, with no pumping or squeezing. A squeeze filter is a bottle you squeeze to push water through the filter. Gravity suits a camp, and squeeze suits a hiker on the move.
How much water does a gravity filter bag hold?
The LONVEAR and Membrane bags hold 1 gallon at a time, and the Waterdrop bag holds 1.5 gallons at a time. A 1-gallon bag is about 8 bottles of 500 ml, and a 1.5-gallon bag is about 11 bottles of 500 ml.
How fast does a gravity water filter flow?
The Waterdrop flows at up to 700 ml/min, the Membrane at up to 500 ml/min, and the LONVEAR at up to 300 ml/min. Flow depends on the source water quality.
Does a gravity water filter need electricity?
No. A gravity filter needs no electricity: gravity pulls the water through the filter. The Purewell countertop system also needs no electricity, with an upper chamber for unfiltered water and a lower chamber for clean water.
How to clean a gravity water filter straw?
Rinse the straw and the bag with clean water, and hang the bag upside down to dry. The Waterdrop straw backwashes with clean water, and the Membrane filter backflushes with no syringe needed.
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