If you are traveling somewhere where the water quality is questionable and you don't want to lug around a good 'mechanical" filter or appropriate purification tabs, the newer UVC water bottles or bottle inserts are a good way to go.
Personally, I use a Grayl "bottle" for this type of thing with good mechanical filtration.
Most UV flashlights are UVB so it is not even remotely good for this type of thing if anyone is curious. You can get UVC flashlights but, due to the risks from inappropriate use, they are not easy to find and purchase.
Modern UVC LEDs are efficient and work very well in lots of applications. If you want to learn more about flashlights and LEDs, Reddit r/flashlights is a good place to start but be prepared for a lot of options and a ton of information, often in conflict due to different needs from different people (sort of like asking someone what is the best shoe??? Runner, Welder, school teacher, soldier, firefighter, ....).
