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Reviews > Hydration Systems > Bladders > Platypus Hoser 3L > Owner Review by Kurt Papke

Platypus Hoser 3L Reservoir - Owner Review

Review Date: November 15, 2007

Personal biographical information

Kurt Papke
6' 4" (193 cm)
220 lbs (100 kg)
Email address
kwpapke at gmail dot com
City, State, Country Minneapolis, Minnesota USA
Backpacking Background: mostly in Minnesota - all of the Superior Hiking Trail, starting on the Border Route.  Dayhiking in Utah, Colorado and Oregon.  Mostly Spring/Fall season hiker.  I often go 1 week without resupply, so I am accustomed to carrying lots of food and water.

Product Information

Cascade Designs/Platypus
Manufacturer website
Year manufactured
Listed: 100 oz (3 L)
Measured: 109 oz (3.22 L)
Listed: 7.5" x 16" (19 x 41 cm) Measured: 7.5" x 17.7"
(19 x 45cm)
Listed: 4 oz (120 g) Measured: 3.8oz (106 g)

Field Information

Location of testing
Minnesota, Utah
Description of location
Superior Hiking trail (210 miles) done in 3 sections over one year.  Elevations: 600 - 1800 ft (180 - 550 m).  Dayhikes in Zion, Bryce, Canyonlands, Arches NP.
Weather conditions
Temperature low of 32 F (0 C), high of 85 F (47 C).  Sun, cloudy and several days of steady rain
REI UL 60 (large size) backpack

General Information

The Hoser reservoir is a water carrier and dispensing system that is principally used inside a backpack, but can also be carried externally on the top or strapped to the front of the pack.  It comprises:
  1. The reservoir itself.  Includes cut slots for hanging from hooks included in some backpack reservoir sleeves.
  2. A coupling that connects the supply tube to the reservoir.  The threaded port is on the bottom of the reservoir, so it cannot be gravity-filled without removing it from the pack.
  3. A supply tube that threads through a backpack hydration port.  Most filters can be rigged with a coupling that can be used to fill the reservoir through the supply tube without removing it from the pack.
  4. A bite valve that keeps water from flowing from the supply tube until compressed with the teeth
  5. A supply tube clip to attach the supply tube to a pack shoulder strap to keep the bite valve accessible

Field Conditions/Usage

I have used two different Platypus 3L reservoirs over the course of the last year on my 3-section hike of the entire SHT and prior dayhikes in Utah.  I always carry the reservoir plus 1-2 20 oz (0.6 L) soft-drink bottles while backpacking.  I consume 5+ L/qt  per day while hiking, and with the dry conditions in Minnesota in the last couple of years I tend to err on the side of caution in assuring that I do not run out of water.

I have carried the 3L reservoir in two different packs, my REI UL 60 backpack and my daypack which also has a hydration sleeve.

I do not always carry the reservoir completely filled.  Since the difference in weight between the 1 and 3 liter reservoir is only one ounce, and since an empty reservoir takes up almost no space in my pack, I carry the 3L as opposed to one of the smaller models.

I carry only water in the reservoir, and use the drink bottles for mixing electrolyte drinks.  On my first section hike I used iodine for purifying my water, which noticeably stained my first reservoir.


The biggest concern I had with using a reservoir was that it would develop a seam leak, or that the coupling would leak as it is on the bottom of the reservoir.  I never have experienced a seam leak from either of my two Platypus units, though between these two I bought a competitor's reservoir which leaked the first day I put it in my pack.  I have had some leakage from the coupling on those occasions where I did not screw it in tight enough.

Filling: I have filled my reservoir directly from faucets, by pouring purified water from bottles, and by direct-filling with my filter through the supply tube.  I prefer the supply-tube method, but on the SHT, streams and rivers are the most common water sources and I have found that it is seldom easy to find a dry spot to set my backpack close enough to the water source that I can plumb a direct connect.  The pattern I have fallen into is to fill the reservoir in camp only, and refill my soft drink bottles during the day.  Outside of a pack, given the height of the 3L unit, it is nearly impossible to keep it vertical to fill without using one hand to hold it.  I have tried holding it between my knees, propping it against a rock, etc. which invariably ends in much cursing as newly-filtered water spills on the ground.  I have not found it necessary to "burp" the reservoir when filling to drain all the air out since the connection is from the bottom.  On the flip side, drinking does not purge any air, so air left in the reservoir after filling is there until it is empty.

Bite valveclipped to strap
: I find that having the bite valve readily accessible and close to my mouth encourages me to stay fully hydrated by drinking often.  The picture to the left above shows the tube/valve clipped to the strap of my backpack.  Water flows readily from the reservoir, though the geometry of the bite valve took me a while to get the alignment just right.  The picture to the right shows the bite valve compressed to illustrate the size of the opening.  I have never observed an off-flavor when drinking from the reservoir.  I have evolved into using the reservoir for water only to avoid cleaning out sugary electrolyte drink residue.

Hanging loopMounting in the pack; my first 3L Platypus eventually failed at the mounting loops - they were simply slots that eventually tore.  My 2007 unit has true loops in the plastic that seem much more robust - see photo to the right.  The newer unit is apparently taller than my prior version, as it tends to slip off the hooks in my pack sleeve, though my backpack is always so tightly packed that the reservoir cannot move.  The photo to the right shows the reservoir hook hanging as there is no tension to hold it in place.  The hanging loop is also so large that the hook passes unhindered through the loop.  It is easy to thread the supply hose through my pack ports by removing the bite valve, though the clip is a little tricky to get through and not easy to remove from the tube.

Cleaning: I generally allow my reservoir to dry out after a hike.  Before the next hike I simply swish it out with tap water.  I do not bother to use bleach or other cleaning chemicals.  I have had no incidences of mold or mildew while storing over winter.


I intend to continue to use my Platypus 3L reservoir.

  1. Reliable (doesn't leak), durable
  2. Connection to bottom of reservoir makes it easy to drink the last few drops of water
  3. No off-flavors
  4. Bite valve is simple to use
  5. Shoulder strap clip makes access easy
  6. Lightweight and space-efficient.  Compress to paper-thin when empty.
  7. Large capacity provides flexibility when long distances between water sources are expected
  1. Not easy to fill without a fitting for filter
  2. 3L size may be too tall for some packs
  3. Bite valve always ends up in the dirt in camp - first drink of the day always has some grit
  4. Bite valve can get caught on branches or other objects and come off supply tube.  I've almost lost it several times.

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Reviews > Hydration Systems > Bladders > Platypus Hoser 3L > Owner Review by Kurt Papke

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