You can find out by visiting the local Technical Supervision Bureau. Samples can also be sent to the quality inspection department. Because if it is a water plant with a formal industrial and commercial license, outsiders cannot evaluate its quality problems. The only authoritative one is the Quality Inspection Section of the Quality and Technical Supervision Bureau. Quality issues include many aspects, such as whether the appearance, outer packaging, trademark, and instructions are standardized, whether the hygiene meets the national drinking water standards, and whether the mineral content in the mineral water meets the standards provided in the instructions, etc. Even though I could taste the difference with my tongue, it had absolutely no legal meaning.

If you want to explain the problem, there is only one way: seal the sample and conduct quality inspection.