While the water itself in a sealed bottle is unlikely to spoil, experts have raised significant concerns regarding the degradation of the plastic containers over time, which may increase the risk of ingesting harmful microplastics. Bottled mineral water typically carries a best-before date of 18 months to two years; however, this date pertains to the plastic bottle, not the water. After this date, drinkers face an elevated risk of consuming microplastics, which have been controversially linked to serious health issues such as bowel cancer, brain damage, and infertility.

Although some experts, like those from the Natural Hydration Council, suggest the water remains safe, others contend that microplastics can enter the water during production and accumulate as the plastic deteriorates. Microplastics are minuscule plastic fragments, as small as two micrometers, and have been detected in various human tissues, including lung tissue, placentas, breast milk, and blood, highlighting their pervasive presence within the body. Dr. Sherri Mason, a leading researcher in freshwater plastic pollution affiliated with the World Health Organization (WHO), emphasized the connection between synthetic chemicals facilitated by plastics and health problems like certain cancers, reduced sperm counts, and increased instances of conditions such as ADHD and autism.

New analysis indicates that over 90 percent of the world's most popular bottled water brands contain microplastics. Recent research reveals that individuals unknowingly ingest tens of thousands of microplastic particles annually, with bottled water drinkers consuming an additional 90,000 fragments per year. While the European Food Safety Agency believes most microplastics are excreted, the UN Food and Agriculture Organisation warns that some particles could enter the bloodstream and lodge in vital organs, linking them to neurotoxicity, chronic inflammation, and disruption of hormones and metabolism.

A study led by Sara Sajedi of Concordia University found that regular bottled water consumers—even when consumed before its expiration date—ingest approximately 900,000 more microplastic particles annually than tap water drinkers. Sajedi highlighted the