Left to right: The CrazyCap, Mahaton and Larq bottles all sanitize themselves with UV-C light. .

The CrazyCap bottle has two water purification modes: normal mode and "crazy mode." According to CrazyCap, normal mode kills up to 99.99% of contaminants and is suitable for "low to medium contamination," such as from public water fountains and tap faucets.

The Larq bottle also has two purification modes: normal and adventure.

You can activate the UV-C purification light whenever you want by pressing the button on the top of the bottle, but Larq also comes to life every two hours for a 10-second cleaning cycle.

The Larq bottle is made of vacuum-insulated stainless steel and keeps your safe drinking water at a cold temperature for up to 24 hours.

The Mahaton self-cleaning water bottle (available for preorder for $44) features one purification cycle that eliminates up to 99.99% of waterborne pathogens?

Unlike the CrazyCap and the Larq, the Mahaton bottle doesn't have an additional purification setting for bodies of water that might contain more contaminants, such as streams and other sources of groundwater.

For that reason, I'd recommend only using the Mahaton bottle with indoor sources of drinking water unless the company releases a new bottle with an additional setting.

The Mahaton bottle can last up to three weeks on a full charge, assuming you run the purification cycle up to four times per day

Which self-cleaning water bottle is best? Truthfully, all three of these water bottles did a great job at keeping themselves clean

I had virtually no complaints about any of these self-cleaning bottles, and if you're looking for an aesthetically pleasing bottle that purifies your water, any of the three will get the job done. 

If you plan on using your self-cleaning water bottle with outdoor sources of water, you may want to opt for the Larq or the CrazyCap since they have overdrive modes that kill even more micro-organisms. 

Most self-cleaning water bottles, including the three covered in this article, also have all the features you'd look for in a normal reusable water bottle: They keep steaming hot water hot and cold water cold (or room temperature water at room temperature), and they're durable. 

How did I test these self-cleaning water bottles? I tested three UV-powered self-sanitizing water bottles -- the Larq bottle, the CrazyCap bottle and the Mahaton bottle (which is on Kickstarter, but is fully funded and already shipping products) -- using the tap water from my apartment's kitchen sink (my preferred water source). 

What to look for in a self-cleaning water bottleYou should consider five important factors when choosing a UV-powered water bottle like these: Purification, taste, design, ease of use, capacity and battery life

If you decide to purchase a self-cleaning water bottle, you'll want one that kills as many microbes as possible, produces a good taste, is easy to hold and transport, and lasts for a decent period of time on one charge. 

Also, how long does it take for the bottle to purify the water

Taste: How does the water taste after going through the purification cycle, compared to my drinking water? 

Does it keep water cold