Australian Hiker

Rating

Platypus Daycap In-Bottle Water Filter Review

This replacement water bottle cap transforms your favourite wide-mouth bottle into a fast and easy water filter. The Platypus Daycap in bottle filter seamlessly fits onto popular wide-mouth water bottles such as Nalgene, Hydro Flask, Camelback and Yeti Yonder-and transforms them into fast, safe and incredibly easy water filters.

Typically the only time I use hard water bottles is when I do shorter day hikes and when I carry enough water for the duration of the hike. In this sense I appreciate I am in the minority given the majority of hikers I pass carrying bottles preferring to use after bladders instead on their trip regardless of length. While water bottles carry water well, I just find that I drink less when I have to access a bottle as opposed to a bladder drinking tube that is located not far from my mouth.

If you are a keen water bottle user then the option exists to use a filter bottle instead. If you are in the market for a new water carrying device then purchasing a filter bottle is a good way to go and in all honesty is the best value for money as purchasing a water bottle and filter purchased as a single unit is cheaper than using a product such as this one. But if you already own water bottles, and we own several, then rather than purchasing a new standalone filter bottle a great alternative is to retrofit an existing bottle with the Platypus Daycap in bottle filter.

This kit comes with an all in one filter cap input good for around 1,000 litres of water, for the standard wider mouth bottle (63mm). The image below shows my water bottle, which has a 63 mm thread. I just removed the cap that came with the bottle and replaced it with the Platypus Daycap in bottle filter. The filter unit is 99 mm long so will suit pretty much any water bottle provided.

This filter is about as easy as it gets. You just screw the cap on and suck water out of the small spout that will allow for a flow of up to 1 litre/hour, there really is no effort with this filter unit. There are 3 things to be aware of though. Like any add on filter unit you need to make sure the filter is secure just like you would with any water bottle top otherwise you run the risk of drinking the contaminated water in the bottle if there are nay leaks. Secondly, an issue with this as well as any other particulate filter, is that if your water source is dirty then using a pre filter of some sort is a good option. An easy option is a Buff. The Buff won’t filter out bacteria or protozoa (that’s what the filters for) but it will get rid of the excessive chunky bits. And lastly this filter unit needs to be replaced very 1,000 litre of use and at the time of this review this was AUD$55.00 RRP, which  for many hikers that will be around 3+ years.

Weight wise this filter is not excessive coming in at 70 grams but when you minus the weight of the existing bottle cap it’s pretty negligable. Price wise this fire cap has an RRP of $116.00 AUD but you can typically find this on offer for a much cheaper price.

So if you are a bottle user and want to add a filter option then have a look at this alternative. Just make sure your existing bottle will fits the caps that come with this filter.

We Like

• Converts existing water bottles to a water filter
• Very easy to use
• Remove solid particles, bacteria and protozoa
• Will suit the most common water bottle sizes

We Don't Like

• Not a dislike as such but most water filters that remove solids will perform better with a pre filter to remove the worst of the grit

Best Uses

Great for hikers with an existing water bottle who want to convert it to a filter bottle

Buy One

You can purchase the Platypus Daycap In-Bottle Water Filter from Wild Earth

Replacement filter available from Amazon Australia

Disclosure: The above link is an affiliate link, meaning, at no additional cost to you, we may earn a commission if you click through and make a purchase. Please note that our affiliations do not influence, in any way, the independence of our reviews. If we don’t like a product, you’ll hear about it from us!

Investment

AUD $116.99 RRP

• Can often be found at a cheaper price

Platypus Daycap In Bottle Filter. This cap turn a standard Nalgene water bottle into a filter bottle

Platypus Daycap In Bottle Filter screwed into a widemouth Nalgene Water Bottle turning it into a filter bottle

Camelbak Eddy+ .75 litre Water Bottle with Platypus Daycap In-Bottle Water Filter easily replacing the standard cap

Platypus product video

Product video from Platypus providing video information

Disclaimer

This review was done by product provided by the Australian distributor of Platypus

Last updated

23 March 2026

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