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How we test reusable water bottles

Here's how we find out which bottles know how to keep their cool.

person holding a reusable sustainable water bottle in a park

Making the switch to a reusable water bottle can help you cut down on single-use plastics and keep closer tabs on your daily water intake. And while you'd think water bottles would be a pretty straightforward subject, there are a surprising number of very average vessels out there. 

Our experts have assessed the performance and ease of use of a range of reusable bottles from big brands like Kmart, Kathmandu, KeepCup and more to help you find the best bottle for your needs.

How we choose what we test

We select reusable water bottles from popular brands that are either available in prominent online and traditional retailers, or ones that have strong brand recognition that you're likely to seek out. The bottles in our most recent test range from $7 up to $85, so you can determine whether more expensive bottles are worth the higher price tag (or if a budget bottle will get the job done).

How we test reusable water bottles


We measure how long it takes for chilled water to warm up in each bottle. First, we drill a hole in the lid that's 0.1mm larger than the thermocouple we use to measure temperature. Then we fill each bottle with chilled water (approximately 3ºC) from a 20L container, attach the lid and insert the thermocouple with the tip as close as possible to the centre of the bottle.

The thermocouples are attached to a logger that records the temperature every 60 seconds. The surrounding ambient air temperature is maintained at approximately 24ºC, and we then wait for the water to reach a temperature of 11.5ºC. The data reveals which bottles are the slowest to warm up, and bottles that stay cool for longer earn a higher score. 

Ease of use

In addition to how well the bottles keep water cool, we also assess:

  • ease of carrying
  • ease of opening and closing
  • how easy it is to drink from the bottle
  • ease of dismantling to clean
  • signs of leaking when the cap is closed
  • condensation on the exterior
  • signs of spills while drinking
  • any strange tastes that may indicate that the bottle has tainted the water.


The CHOICE Expert Rating (our overall score) is made up of performance (50%) and ease of use (50%).

We care about accuracy. See something that's not quite right in this article? Let us know or read more about fact-checking at CHOICE.

Stock images: Getty, unless otherwise stated.