Doctor’s orders: drink lots of water! Large daily intakes of water have been proven beneficial to one’s health, by keeping people at a healthier weight, hydrating the organism and the skin and even partially detoxifying the body. But which water is more beneficial? The question is not about bottled water brands, but it’s more related to the chemicals that are put into everything we consume.

A study conducted in California on top bottled water brands has shown that the water is contaminated with several substances, known to damage your health. Among these, researchers have found chemicals linked to cancer development in quantities thrice as big as the Californian health standards allow. This is yet further proof that contests the popular belief that bottled water is in any way better than regular tap water. Among the substances identified, scientists found coliform bacteria, acetaminophen, solvents, fertilizers, strontium – a radioactive element – and even traces of caffeine.

The study was conducted over a period of two years, on bottled water batches belonging to 10 popular, widely consumed brands. Only two brands on the 10 analyzed showed signs of high-risk contamination, contamination linked either to plastic bottle leaching or tap water pollutants. That theory, however, does not explain the traces of arsenic in the two brands’ bottled water.

The high levels of the substances identified should not be present in bottled water, researchers said, mostly worried about the causality links between the substances and the developing of cancer. Wal-Mart’s brand, for instance, had 5 times the California health standard allowed amount of bromodichloromethane. People have been advised to use a carbon filter on their tap for drinking tap water until the contamination issue is solved.