Analies Dyjak, M.A. & Christina Liu, B.S.   

A common question our Water Nerds get asked is if it’s safe to drink or cook with hot water from their faucets. People often choose to use hot water to speed up the boiling process when making pasta, tea, etc. However, the time saved is not worth the potential of health outcomes that can come from doing so. Here’s why you should stick to using cold water for drinking and cooking.

Risk of Chemical Contamination

Lead and zinc (commonly found in water pipes) are more soluble in hot water than in cold water. So when you run hot water through the pipes, lead and zinc are much more likely to leach into the water coming out of the faucet. If you live in a house built before 1986, when lead pipes were banned, you definitely want to avoid drinking tap water from your hot water line. Also, boiling water doesn’t remove chemical or metal contaminants, like it does for biological contamination. 

Risk of Bacterial and Biological Contamination

Hot water tanks can act as biological incubators and grow bacteria. Legionella, which is the bacteria that causes Legionnaires Disease, thrives in warm water environments and is commonly found in hot water heaters. There are an estimated 22,000 cases of Legionnaires Disease reported every year in the U.S. The hot water heater can also collect all sorts of residue buildup and gunk. You really don’t want any of that in the water you’re ingesting.

What Do The Experts Say?

CDC: “Drink or cook only with water that comes out of the cold tap. Water that comes out of the warm or hot tap can have higher levels of lead. Boiling this water will not reduce the amount of lead in your water.”

EPA: “USE ONLY COLD WATER FOR COOKING AND DRINKING. Do not cook with, or drink water from the hot water tap. Hot water can dissolve lead more quickly than cold water. If you need hot water, draw water from the cold tap and then heat it."

Professional Chefs & Food Writers: “There is…a good reason to use cold water instead of hot for cooking: hot water will contain more dissolved minerals from your pipes, which can give your food an off-flavor, particularly if you reduce the water a lot.”