HydraPak
HydraPak Stow 1 L Flexible Bottle
- Weight for its size: 10/10 How much it adds to your pack for the water it holds.
- Packed size (empty): 8/10 How much room it takes up when it is empty, for the water it holds.
Lowest price we found
£19.99 at Ultralight Outdoor Gear
Go to Ultralight Outdoor Gear Compare 2 shopsUltralight and long-distance trips where an empty bottle should roll up small
- Type
- Soft
- Capacity
- 1 L
- Weight
- 51 g
- Packed
- Not published
Where to buy
Ultralight Outdoor Gear £19.99 In stock. Free delivery. Shop shows RRP £20.99. Free tracked UK delivery on all orders (header: free over £15).
View at shop: Ultralight Outdoor GearHydraPak £21 In stock. HydraPak's UK shop. Free UK shipping from £50 (its page also says £75); below that the cost is shown at checkout.
View at shop: HydraPakPrices checked 8 Nov 2026 on each shop's own page; shops can change them. We earn no commission on these links; shops are listed by price. More
Our ratings (out of 10)
1 to 10, compared with the whole market. Each says what it's based on. How we score
Weight for its size
From maker's figures 10/10How much it adds to your pack for the water it holds. 10: The best you can buy for this.
HydraPak lists 51 g for 1 L: 51 g per litre, under 100 g/L.
Packed size (empty)
Estimate from maker's specs: soft bottle: rolls up when empty 8/10How much room it takes up when it is empty, for the water it holds. 8: Clearly better than most.
Estimate from maker's specs
What reviewers say (out of 10)
Ratings marked * are from reviews and are not part of the trip score. They are reviewers' scores, not our own measurements. How we score
Leakproof*
Reviewers' average 9/10How reliably it stays sealed in a packed rucksack.
5 reviews on leakproof, e.g. "They have been leak proof and functioning properly since I've had them.".
Durability*
Reviewers' average 8/10How well it survives knocks, drops and daily use.
3 reviews on durability, e.g. "appreciated its durability, where we even felt comfortable having our dog carry it".
In short
Good for
- Ultralight and long-distance trips where an empty bottle should roll up small
- The dirty-water bottle for a squeeze or screw-on filter with a 28 mm thread
Strengths
- 51 g for 1 L, about half the Ultralite HDPE Nalgene (106 g)
- Rolls up when empty and stows in its bail handle
- Flip-top cap protects the spill-proof silicone nozzle
- Fits most 28 mm threaded filters, including HydraPak's own 28 mm filter kit
- Internal baffle keeps a slim, easy-to-hold shape when full
- One reviewer used it leak-free for over two years
Weaknesses
- Soft and floppy when full; the 1 L feels awkward in the hand (Find Your Haven)
- You have to squeeze or suck hard to drink (Tang Trails)
- Slow to dry, and the first fill can taste of factory plastic: wash with soap before use (Tang Trails)
- No stiff body to slot into a bottle pocket: stuff it in a pocket or hang it from a small carabiner (Find Your Haven)
- Only 1 source on the current version speaks about durability
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.
ShowHide sources (7)
- HydraPak: Stow 1 L collapsible water bottle (spec page)
- Toolsdoctor (YouTube): Tested, HydraPak Stow full review (1 L and 500 mL, with the flip cap)
- Tang Trails (YouTube): HydroPak Stow 1L review (first three hikes)
- Find Your Haven Outdoors: Review, HydraPak Stow collapsible water bottle (over two years of use, 1 L and 500 mL)
- Treeline Review (Sam Schild): Best Running Water Bottles of 2026, HydraPak Stow 1 L entry (updated 10 August 2026)
- HydraPak customer reviews: Stow 1L (84 of the 248 on the shared Stow feed, 60 flagged verified buyers; all 248 read; maker's own Okendo feed)
- Adventure Outdoors (YouTube, Steve Sherron): The Ultimate Guide to HydraPak Collapsible Water Bottles, Stash, Flux & Stow (the Stow 1 L segment, flip-up top, with a full-bottle drop test; Amazon affiliate links disclosed)