DIY gravity system using a Sawyer Squeeze or Hydroblu Versa Flow water filter

No more pumping or squeezing! Convert a Sawyer Squeeze or HydroBlu Versa Flow water filter and let gravity do the work of filtering water.

DIY gravity water filter setup

Gravity systems are great for quickly filtering a large quantity of water for use at camp while backpacking. After using the Sawyer Squeeze for filtering water on backpacking trips for several years, I found the process of squeezing the bag to be a tedious task. I was planning to purchase a gravity filter, but decided to use the Sawyer Squeeze filter and make my own gravity system. This DIY project not only saves money, it also saves weight! I now use the HydroBlu Versa Flow filter, which is similar to the Sawyer. Both work equally well in a gravity system.

How does the gravity system work?

Basically, you collect ‘dirty water’ to be filtered in a water collection container, attach a filter, connect a hose to the filter and to a ‘clean water’ storage container. Hang or lift the ‘dirty water’ container up higher than the ‘clean water’ container, allowing gravity to pull water through the filter, down the hose and into your storage container. It only takes a couple of minutes to filter two liters of water using this method, and since it’s hands-free, you can attend to other camp chores while filtering water.

Gear for Setting Up a Gravity System

My setup uses a CNOC Vecto bladder as the water collection container with a HydroBlu Versa Flow water filter. For connecting to the Versa Flow Collapsible Canteens that I use for water storage, I attach a silicone hydration tube using the Sawyer Fast Fill Adapter Kit. While it is possible to filter without the hose and adapters, the flow rate will be faster when gravity is involved via a longer section of hose.


water filters for backpacking

You’ll need a filter with threading or attachment points on both ends for this setup. I’ve used both the Sawyer Squeeze and the Hydroblu Versa Flow in my gravity system and prefer the Versa Flow over the Sawyer Squeeze. Sawyer Mini and Micro filters will also work, although the flow rate may be slower.


filtering water for backpacking

This system requires a water collection container that a filter can be threaded onto. I started out using one of the bags that came with the Sawyer filter. However, I found that the Sawyer bag wasn’t easy to collect water in. The opening is small so it’s not easy to quickly fill. Also, the action of swishing it back and forth in the water source tends to stir up sediment that ends up in the bag and could eventually get into the filter. It was around this time when the CNOC Vecto bladders came onto the market. They were designed by a thru-hiker who wanted a better way to collect water for filtering. The Vecto can be filled much easier, with a wide opening on one end, and a threaded opening on the other that the filter can be attached to. I added a short section of cording so it could be hung from a tree.

Adapting a Sawyer bag for hanging: cut small round holes in the bottom of the 64oz Sawyer bag, being careful to not cut through the part that holds water. I used a paper hole punch. Add cording through the holes and tie knots to securely hold the bag when it’s full of water. I used  bowline knots.


water storage containers for backpacking

This system will work with any of the following:

  • soft water bottle (HydroBlu Collapsible Canteens, Platypus Soft Water Bottle, etc.)
  • hydration bladder (needs to have a hose you can disconnect)
  • disposable plastic water bottle (Smart Water, Life Water, etc.)
  • Nalgene or other hard-sided water bottle

Initially, I started out using a hydration bladder but I’ve since converted to using the HydroBlu Collapsible Canteens for storing water at camp and a Smart water bottle for use when hiking and for drinking water at camp. I made this change because I don’t like hauling the hydration bladder around at camp when I need water for drinking or cooking, and not having water in a bladder inside my pack eliminates a potential problem with the bladder leaking and getting gear wet. As a bonus, my new setup weighs a lot less.

  • Hydroblu Versa Flow Collapsible Canteen 2 liter water storage container: purchase from: HydroBlu


connections for gravity setup

For a greater flow rate, I connect the filter to the storage container using a 24″ length hydration hose. If you are using a hydration bladder in your system, the hydration hose for your bladder can be used for this purpose.

The adapter kit is for connecting the filter and collection container to a hydration hose for hands-free filtering. There are three small plastic parts in the kit, and what you’ll need with vary based on which filter and storage container you are using.

For use with a HydroBlu Versa Flow, Sawyer Mini or Sawyer Micro: attach one end of the hydration hose directly to the outflow side of the filter. No adapter part is needed for connecting to the filter. Add an adapter to the other end of the hose for attaching to the storage container.

For use with a Sawyer Squeeze: Attach the Fast Fill Kit’s blue plastic part (threaded on one end with a short section of hose and adapter on the other end) to the outflow side of the filter. On one end of a hydration hose, place an adapter that will connects to the adapter attached to the filter.

For use with a water bottle with a small threaded opening (either a soft water bottle or a disposable plastic water bottle): Attach the Fast Fill Kit’s blue plastic part (threaded on one end with a short section of hose and adapter on the other end) to the water bottle’s opening. Then add an adapter that connects to this on the hydration hose.

For use with a hydration bladder: Disconnect the tube from your hydration bladder, cut your hydration tube about 6″ from the bite valve and attach one of the small adapters to one side of the cut tube, and the large adapter on the other side so they will connect together. Some hydration tubes have a small connector on this end that is identical to the small adapter in the Fast Fill Kit.

Add a clamp (shown above in the photo on the left) to the hose to make the process of connecting and disconnecting the various parts easier without spilling water all over.

How to filter water using a gravity system

gravity water filter setup

Step 1: Fill your water collection container with ‘dirty water’, being careful to not get small debris into the bag. The CNOC Vecto has a wider opening for the easiest method of collecting water. After filling, replace the slider to close the bag. When using a Sawyer bag, I use a cut-off water bottle for scooping the water and pouring into the small opening on the bag.

Step 2: Attach the filter to the water collection container’s threaded opening.

Step 3: Reconnect the tube to the hydration bladder, then connect to the filter using the plastic adapters, which will click when connected.  Note: the water will begin to flow as soon as the bag is hung, so connect everything before hanging the bag.

Step 4: Hang the ‘dirty water’ container from a tree or hold it up high enough for water to filter through.

Kick back and relax while gravity does the work! If the water stops flowing into the storage container, you may need to release air from it so water can fill it completely.


If you are filtering a lot of water, or if the water has sediment, you will probably need to backflush the filter on an overnight trip. There are two methods I’ve used to backflush without using the plastic syringe that comes with the Sawyer Squeeze:

  • With at least a liter of clean water in your storage container, reverse the water flow by holding the clean water container above the dirty water container long enough to flow the water back through the water filter, which is the same as backflushing. After this process is finished, you can re-filter this water into your clean water container.
  • Or using the sports cap on a water bottle filled with clean water, hold the sports cap over the ‘out’ valve on the filter and squeeze all of water through the filter. You are reversing the water flow, so make sure to push water from the ‘out’ valve so the water comes out of the ‘in’ valve. Otherwise, you are just filtering the water again and not cleaning the filter.
  • After backflushing, detach the filter and shake the water out so any debris lodged in the filter will fall out.

Post-trip clean up

After each backpacking trip, I rinse out the water filter and all collection containers. Lay them out to dry thoroughly before putting away to eliminate issues with mold and mildew. Some people keep their hydration bladder in the freezer to keep bacteria from growing, but I’ve never needed to do this. After several backpacking trips, I use a cleaning tablet made for hydration bladders and tubing, and a drop or two of bleach in a gallon of water to backflush and disinfect the water filter.

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