Hot water boils faster, so to save time in the kitchen, you might be tempted to cook your pasta with hot tap water. This time-saving trick is bad for your health. The problem is lead.
Hot water is much more likely to leach the heavy metal from your plumbing pipes. Using lead to solder pipes wasn't banned until 1986, and unfortunately brass plumbing parts might contain a bit of lead as well. Plumbing parts legally considered lead-free today may contain up to eight percent lead. This means your chances of having lead-free plumbing are slim.
Why does it matter? Well, too much lead in the body can cause serious damage to the brain, kidneys, nervous system, and red blood cells (it's especially bad for pregnant women and children). So the EPA recommends that you do not use water taken from the hot tap for cooking or drinking, and especially not for making baby formula. If you need hot water, draw water from the cold tap and heat it on the stove. Anytime a faucet hasn't been used for at least six hours, "flush" all the water that has been sitting in the pipes. This could take anywhere from five seconds to two minutes. When the water stops getting colder, it is "flushed." I live in a state that is currently experiencing a drought, so I use this water for houseplants and potted plants on the deck.