Is bottled water really better than tap when it comes to drinking water? When it comes to hot water, it may be. A recent NY Times article points to research conducted by environmental scientists that hot tap water is more likely to be contaminated with lead than cold water. The reason for this is that hot water will dissolve anything – including contaminants like lead – much more easily than cold water and if that water encounters something like an older leaded pipe or some rust before coming out in your kitchen sink, it could very well end up in your glass. The risk, which accounts for up to 20% of all lead exposure, can be increased by further heating the water, because the lead will become more concentrated as water evaporates.
The risk is minimized by using cold water, so it’s probably best not to use hot tap water when drinking or cooking, even if using hot water will speed along the process of boiling water or fixing dinner.