Platypus Big Zip EVO review: the easy-clean hydration reservoir
Once you have hiked with a hydration reservoir, stopping to dig out a bottle feels like a chore. The Platypus Big Zip EVO is the reservoir for people who actually want to keep theirs clean — a taste-free bladder whose whole top slides open so you can fill it, scrub it, and dry it without a fight.
The verdict
The easy-living reservoir. The Big Zip EVO gives you hands-free drinking on the move with two things buyers prize most: genuinely taste-free water and a wide SlideLock top that opens the whole bladder for fast filling and, crucially, easy cleaning and drying. Add a high-mount quick-disconnect tube and a fast-flow bite valve and it is the reservoir most hikers will be happiest living with day to day. It costs more than a bottle and, like all bladders, hides inside your pack so you cannot eyeball what is left. If you want a reservoir you will actually keep clean, this is the one.
What it does
The Platypus Big Zip EVO is a hydration reservoir — a flat water bladder that rides in your pack’s sleeve with a drink tube routed over your shoulder, so you sip on the move without stopping or reaching for a bottle. Its signature is the SlideLock top: the entire top edge opens with a sliding clip, giving you a wide opening to fill fast under a tap or in a stream, and — the part that matters over a season — to reach inside for cleaning and to prop open for drying so it never gets funky. The water is famously taste-free (no plastic tang, even on the first fill), the drink tube is a large-bore, fast-flow line with a self-sealing HyFLO bite valve, and a high-mount quick-disconnect lets you detach the tube to refill without pulling the whole bladder out of your pack. There is a shut-off valve to stop flow, it is made in the USA, and it carries a limited lifetime warranty. It comes in 2 L and 3 L sizes to match your day.
What verified buyers say
Verified-purchase owners — many of them converts from other reservoir brands — line up behind a few points:
- No plastic taste. The most repeated praise: the water tastes clean from the first fill, where cheaper bladders taste of chemicals — several say it is why they switched from other brands.
- Easy to fill, clean, and dry. The big top opening lets owners fill fast, reach inside to wash, and dry it properly, which is the usual pain point with bladders.
- Great flow and handy quick-disconnect. Buyers like the fast flow and the push-button tube release for topping up without unpacking, and note it freezes without damage.
- Durable in hard use. Military and long-trail users report it holding up where they had replaced other bladders.
Worth knowing
A couple of honest notes. The plastic SlideLock closure bar is the weak point a few owners mention — do not carry the full bladder by it, and treat it gently; it is the part most likely to crack or slide off. As with any reservoir, the bladder disappears inside your pack, so you cannot glance at how much water is left the way you can with a bottle — learn to judge by weight, or carry a marked bottle alongside for meal water. And every reservoir needs post-trip care: empty it, wash it, and dry it fully (or freeze it between trips) so it never grows mold. Do that and the Big Zip stays fresh for years; skip it and any bladder turns nasty.
Who it is for
The Big Zip EVO is for the regular day-hiker, backpacker, or mountain biker who wants hands-free hydration and values clean-tasting water and painless cleaning above all. It is the reservoir to pick if your last bladder tasted like plastic or grew mildew because it was a hassle to dry. If you want the toughest, most abuse-proof reservoir with an insulated tube for hot or freezing conditions, compare the HydraPak Force. If you would rather keep it simple with a bottle you can see and measure, the Nalgene 32 oz is the classic. And always treat the water you scoop — see our Sawyer Squeeze review.
Specs at a glance
Type: hydration reservoir (2 L / 3 L) · Opening: full-width SlideLock top · Valve: HyFLO fast-flow, self-sealing · Tube: high-mount quick-disconnect · Taste-free; made in USA; lifetime warranty · Best for: hands-free hikers who want easy cleaning
The Verdict
The Platypus Big Zip EVO is the hydration reservoir most hikers will be happiest with: clean-tasting water, hands-free sipping, and a wide top that finally makes filling, cleaning, and drying easy. Want the most rugged reservoir with an insulated tube for extreme heat or cold? Compare the HydraPak Force. Prefer a simple bottle you can see and measure? See the Nalgene 32 oz. Going ultralight with a gravity filter? Look at the CNOC Vecto.
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