Basics Food Safety Is Re-Boiling Water Safe? By Shereen Lehman, MS Shereen Lehman, MS, is a healthcare journalist and fact checker. She has co-authored two books for the popular Dummies Series (as Shereen Jegtvig). Learn about our editorial process Shereen Lehman, MS Fact checked by Fact checked by Elaine Hinzey, RD on June 08, 2020 linkedin Elaine Hinzey is a fact checker, writer, researcher, and registered dietitian. Learn about our editorial process Elaine Hinzey, RD Updated on June 08, 2020 Print Bill Boch / Getty Images Consuming re-boiled, clean, uncontaminated drinking water will not cause cancer or poison you or your family. As long as your water comes from a source that is regularly inspected, you can boil it as many times as you want. When Re-Boiling Water Can Be Unsafe The idea behind this myth is that boiling water concentrates any solid substances that are in the water. Maybe you've seen white chalky stuff stuck to the sides of your pot or tea kettle after you've boiled water. It's just calcium, which is harmless. As long as there's nothing bad in your water to concentrate, there's no health concern. So what if there is something nasty lurking in your water? If your water contains arsenic, lead or nitrates, then boiling it will increase the concentration of those substances. At what point does it become dangerous? That's hard to tell, but that's why water needs to be regularly inspected. Foodborne Illness and Food Safety The levels of both nitrates and arsenic are regulated, and water supplies must be monitored in towns and cities, so if your tap water comes from a city water source, it's safe. These toxic substances can get into your water in a variety of ways. Groundwater may contain nitrates, which are chemicals often found in fertilizer, and arsenic that may occur naturally or from a farm or industrial waste. If you live in a rural area and have a well, the water must be tested. Lead doesn't come from the water source itself. The contamination happens at home. Lead can contaminate a water supply through old plumbing that's held together with lead solder or stored in tanks lined with lead. Exposure to lead can cause emotional and behavioral problems. Lead can't be used for plumbing anymore, but it might be present in buildings and houses built before 1986. Is It Safe to Reuse a Plastic Water Bottle? Was this page helpful? Thanks for your feedback! Looking to lose weight? Our nutrition guide can help you get on the right track. Sign up and get it free! Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Centers for Disease Control and Prevention. Arsenic and Drinking Water from Private Wells. Updated July 1, 2015. United States Environmental Protection Agency. Chemical Contaminant Rules. Updated July 27, 2018. MedlinePlus. Lead Poisoning. Updated August 4, 2020.