Platypus
Platypus DayCap In-Bottle Filter
- Protection: 8/10 What it removes from water, and how well that is proved.
- Flow rate: 4/10 How fast clean water comes through when it is new. Real flow drops as it clogs: see Ease of use.
- Weight: 9/10 How much it adds to your pack.
- Ease of use: 9/10 Filling, squeezing or pumping effort, how fast it clogs in peaty or silty water, and how easy it is to clean.
Day walks and short trips where you drink from streams as you go
- Type
- Bottle
- Removes viruses
- No
- Flow
- 1 L/min
- Weight
- 74 g
- Pore size
- 0.2 µm
- Rated life
- 1000 L
Where to buy
John Bull Clothing £34 In stock. Delivery £5.95. Stock shown as 5 units. Delivery from its delivery page: £3.50 under £10, £4.95 from £10 to £19.99, £5.95 from £20 to £69.99, free from £70.
View at shop: John Bull ClothingUltralight Outdoor Gear £37.99 In stock. Free delivery. Shown with an RRP of £44.99. Free tracked UK delivery on all UK orders.
View at shop: Ultralight Outdoor GearCotswold Outdoor £45 In stock. Delivery £6.95. Shown with RRP £45.00. UKC's July 2025 review gave £40, so the list price has probably risen since. £6.95 delivery under £125, free Click & Collect.
View at shop: Cotswold OutdoorPrices 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
Protection
From maker's figures 8/10What it removes from water, and how well that is proved. 8: Clearly better than most.
0.2 µm hollow-fibre filter. Platypus says each one is individually tested to EPA and NSF guidelines for 99.9999% of bacteria and 99.9% of protozoa: a named standard for bacteria and protozoa, so 4. No virus claim.
Flow rate
From maker's figures 4/10How fast clean water comes through when it is new. Real flow drops as it clogs: see Ease of use. 4: A bit below average.
Platypus gives 1 L/min, drinking through the spout with a new filter and clean water. 0.6 to 1.19 L/min. UKC found it took a few flushes of water through the filter to reach full flow.
Weight
From maker's figures 9/10How much it adds to your pack. 9: Among the best you can buy for this.
74 g for the cap and filter (Platypus). Under 90 g. UKC and Ultralight Outdoor Gear both give 65 g: same band. You also carry a wide-mouth bottle, which is not counted.
Ease of use
From reviews 9/10Filling, squeezing or pumping effort, how fast it clogs in peaty or silty water, and how easy it is to clean. 9: Among the best you can buy for this.
Fill the bottle and drink: no squeezing, pumping or backflushing, and UKC cleans a clogged filter by shaking the bottle half full for 30 seconds. SectionHiker (5) and Hiking Trails (5) rate it very easy. Treeline (4) says it takes only a light pull, almost as easy as normal drinking, but is awkward for moving water into a pot. UKC (4) found it needed a few flushes to reach full flow. Average 4.5 out of 5, so 9 out of 10. Treeline's write-up is part of its water filter roundup, with its own hands-on test of the DayCap. SectionHiker had a free sample, which it says.
In short
Good for
- Day walks and short trips where you drink from streams as you go
- Turning a wide-mouth bottle you already own (Hydro Flask, Yeti Yonder, CamelBak) into a filter
- Fast days where you refill at sources
- Travel where tap water is doubtful
Strengths
- No squeezing or pumping: you drink through the spout
- 74 g and no extra bag to carry
- Shake to clean in the field
- Flip-up spout cover
- Rated to 1,000 L
Weaknesses
- Fits wide-mouth bottles only
- Your bottle becomes the dirty bottle and has to be kept apart from clean water
- Rated to only 1,000 L
- Not safe after freezing: Platypus says not to drop or freeze the filter
- Does not remove viruses
- Slow to start: a few flushes to reach full flow (UKC)
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.
ShowHide sources (6)
- Platypus (Cascade Designs): DayCap In-Bottle Filter, specs
- Platypus: DayCap instruction manual (do not drop or freeze)
- SectionHiker (Philip Werner): Platypus DayCap In-Bottle Filter review (free sample, disclosed)
- UKC Gear (Rebecca Ting): Platypus DayCap In-Bottle Filter review
- Hiking Trails (Katie Mitchell): Platypus DayCap In-Bottle Filter review (four days in Yosemite)
- Treeline Review: Best Backpacking Water Filters (field-tested)