Distilled Water Assessment

Containers of distilled or purified drinking water were purchased at twelve different locations around the Twin Cities. Some of the products were simply labeled as distilled water; others were labeled as distilled or purified water intended specifically for infant formula use. Some of the products were purified by distillation, others by reverse osmosis. The water samples were analyzed at the MDH Public Health Laboratory for various metal and organic contaminants. We did not expect to find high levels of contaminants in the purified bottled water because purification processes are very effective at removing contaminants. However, we also did not expect to find completely contaminant free water, as some contaminants can persist after treatment and some can enter the water after treatment.

Most of the compounds we tested for were not found in any of the samples. The few compounds that were detected were mostly volatile organic compounds (VOCs) or chlorinated solvents, and these were detected at levels well below health guidelines. VOCs are contaminants that can move easily from water to air, so it may be that the treatment processes for water were less effective at removing these compounds. There was little evidence of contaminants entering the water from the plastic bottles.