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Waterdrop Filter Straw with Gravity Water Bag Kit

rated 4.0 of 5 stars
photo: Waterdrop Filter Straw with Gravity Water Bag Kit pump/gravity water filter

The Waterdrop is a versatile water filter system that can be used as a simple straw for a solo traveler, or in conjunction with the included gravity kit to serve a small or medium group. It’s lightweight but sturdy, if not a bit bulkier than some competitors’. Fast water flow and quality of the filtered water is slightly above average according to my experience, making it a good option for camping, backpacking, or traveling.


  • Large water bag (1.5 gallon)
  • Quick waterflow
  • Well made (all parts)
  • Active carbon fibers improve taste of water


  • A bit bulky
  • No adapter for the water outlet tip
  • Water outlet cap can get lost

Before researching Waterdrop, I had no idea the company had a massive line of water filters for every application possible, from home to camper/RV and outdoor, and even reverse osmosis systems.

That tells me Waterdrop has some background and experience with water filtering, so I decided to try their compact straw-type backpacking gravity filter system.

The complete Waterdrop Gravity kit. 

The Gravity Water Filter is a camping-backpacking straw-type filter that can be purchased solo or as a gravity kit with the following items:

  • A 1.5-gallon rugged, BPA-free, food-grade TPU unfiltered water pouch with a hanging strap;
  • A canister to connect the water bag to the straw filter;
  • One 600ml/20oz. Simple plastic water pouch (can be used for filtered or unfiltered water). 

The filter has 28mm threads to connect with ordinary water bottles and other SP400/410/415 size ranges like other compact filters, such as the Sawyer line.

The 600ml plastic pouch has a 28mm thread that fits into the ‘dirt water’ entry of the filter for drink-on-the-go (or be used to store filtered water if preferred).

Filtering system.

The filtering element is also very typical: a 0.1-micron hollow membrane made from coconut shell activated carbon fibers to retain bacteria, protozoa, and other harmful substances and remove odor and taste. According to Waterdrop, it should be good for about 100,000 gallons, but that varies according to usage (water source quality, etc.) and maintenance.

The filter must be backwashed after every usage, according to Waterdrop. I admit to forgetting and skipping this step from time to time, but I didn’t notice any change in the water flow after two or three filtering cycles of the 1.5-gallon bag without washing. Maybe this will play into long-term durability, so it’s best to stick to the recommendations.

Instructions printed on the tough TPU water bag.

Water quality.

I had the opportunity to directly compare the same water filtered by the Waterdrop, Sawyer, and the Grayl filters on a few occasions and found it slightly better tasting than the Sawyer and more similar to the Grayl, which also has an activated carbon filter.

The Waterdrop won’t filter out viruses; in case of suspect water (usually near human concentrations), it’s best to boil or treat with chemicals or UV after using the filter. Otherwise, the filter will handle the most common impurities and provide good quality—great-tasting water from various quality sources.

The connection valve will stop the bag from leaking and allow the flow into the canister once connected. But it’s a ‘system’  and can only be used as such. 

Construction and other aspects.

I‘m quite impressed with the construction of the Waterdrop gravity kit. The “dirty” gravity water bag is tough and should last long. The 1.5-gallon capacity is more than enough for me, whether I’m solo or with a small group. It’s almost three times the capacity of my CNOC Vecto (2L) and can practically fill my Sea to Summit Watercell X (6L, reviewed here on Trailspace). I even used it for showering a few times.

The only drawback is the proprietary connection system. It’s pretty clever and functional but only works together. Disconnecting from the bag will interrupt the flow and prevent leaking. When connected, it’ll open and flow into the canister. It may break if stepped onto, rendering the bag unusable for filtering as intended. Waterdrop sells replacements for all items; be aware of these inconveniences.

Good flow when used either as a straw or gravity system.

The Waterdrop has a good flow for a straw filter; it’s considerably faster than my Sawyer and much easier than the hard-pressing Grayl. It fills my 6L Watercell X in less than 5 minutes and my 1.2L bottle in 1:30 minutes. Clicking the plastic clamp or raising the canister above the bag’s bottom stops the flow. 



At first, I found the sturdy nylon strap a bit bulky and clumsy, but I soon realized its functionality. It’s easy to hang the bag on branches, fences, roof beams, or anything. But it can also carry the load, and I found it excellent.
The nylon webbing is large and comfortable on the shoulders even for long periods and with the bag full of water, and leaves the hands free to carry other stuff or help climbing ditches and all.

The Waterdrop bag hanging from a tree branch next to my Sea To Summit Watercell X. 

The not so great.

The filter must be backwashed, which doesn’t bother me at all. But I wish a few designs could be improved:

  • The removable cap separates from the filter body and may be easily lost or forgotten. For that reason, it also gets dirty quite frequently. 
  • The plastic flow clip can break and requires care and attention.
  • The filter’s mouthpiece can’t be used with a canister or other piece to direct the filtered water into the clean pouch or bottle, so in most cases, it must be held during filtration, mainly if the reservoir’s mouth is small. Fortunately, the flow is excellent and fast, so it’s not a deal breaker, but it could be more convenient, which is the whole point of a gravity system, in my opinion. 
Depending on the settings and setup you must hold the straw while filtering. 
The plastic flow clip works but will break if steeped onto. 


Overall, I’m very satisfied with the Waterdrop Gravity Filter. It’s easy to set up and use, sturdy, works well, and the water tastes very good. I’ve used it on various water sources, holding well.

I can’t comment on long-term durability, but Waterdrop rates the straw filter for 100,000 gallons, so it should last a few good years, at least. Besides, it’s not expensive, so there’s that aspect too.


I’ve been using different systems, types and brands of water filtration for my traveling and outdoor activities for many years. We don’t have any deserts here but decent, filter-able water may not be abundant or easily found in some places, so “water strategy” is important and I like to carry the least amount necessary due to the weight of the liquid, so treatment is important to me.

Source: bought it new
Price Paid: USD 43

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Price MSRP: $36.99
Reviewers Paid: $43.00
Pouch Capacity 1.5 gallons
Filtration Capacity 100,000 gallons
Filte Pore Diameter 0.1-micron hollow fiber membrane
Filterstraw 1.38 x 7.09 in
Collapsible water pouch 5.7 x 10.7 in
Gravity water bag 8.8 x 16.7 in
Product Details from Waterdrop »