Do UV-C self-cleaning water bottles really purify tap water?

Reviewers generally agree UV-C is effective at neutralizing bacteria inside the bottle and improving taste/odor, and Consumer Reports' coverage of LARQ describes the UV-C LED as legitimately reducing bio-contaminants. However, retailer reviewers at Best Buy and others caution that UV-C alone is not a substitute for a proper filter when the source water is questionable — it won't remove heavy metals, chemicals, or particulates. For dubious water sources, a bottle with both UV-C and a filter (like the LARQ PureVis 2) is the safer bet.