Water hardness

Hardness is a measure of the presence of calcium ions, as well as other ions such as magnesium, iron and manganese.

Hard water can cause scale to form on boilers and hot water pipes and fittings.

To minimise undesirable build-up of scale in hot water systems, total hardness (as calcium carbonate - CaCO3) in drinking water should not exceed 200 mg/L.

The typical hardness level of water delivered in South East Water's area is between 12 – 45 mg/L. This means that the water being supplied to South East Water customers is considered "soft" by international standards.