Centimetre of water

A centimetre of water is a way to measure how high water is. Imagine you have a big bucket of water and you want to know how deep it is. Instead of saying it's 10 inches deep, you can say it's about 25 centimetres high. A centimetre is a little bit bigger than the size of your fingernail, and water is very important because we need it to stay healthy and clean. So if you ever hear someone talking about a centimetre of water, they just mean how high the water is in a certain place.