I left my water heater at 70 °C all summer just to be safe: the day a plumber opened the tank, I saw what those extra degrees had built up inside
A homeowner’s attempt to protect against bacteria by running their water heater at 70°C (158°F) all summer created a nightmare of mineral buildup. What started as a safety instinct turned into a structural disaster that accelerated tank failure and wasted energy—all for protection that wasn’t even necessary.