is filling the kettle beyond its maximum level.

Most kettles have minimum and maximum water markings. Stay within those limits.

Overfilling can allow boiling water to escape through the spout or lid, increasing the risk of burns.

At the other extreme, operating a kettle with too little water can trigger the boil-dry protection—or, if that protection fails, potentially damage the heating element.

Don’t Keep Reboiling Water Forever

There’s also a popular claim that repeatedly boiling the same water turns it into something dangerous.

The reality is more nuanced.

For normal