Water of sufficient quality to serve as drinking water is termed potable water whether it is used as such or not.

On ships
Potable water tanks on a ship are small compared to cargo tanks or ballast tanks. A cargo ship has typically two or three fresh water tanks with an overall volume of about 100 m³. Large passenger or cruise vessels can have potable water tanks of more than 500 m³ to provide its passengers with drinking water.
Potable water tanks made of carbon steel need to be coated internally with a lining that will protect the steel tank from corrosion and ensure that it retains its structural integrity.

Onshore
Large elevated onshore potable water tanks or water storage towers can hold more than
100 000 m³ drinking water. Onshore potable water tanks can be made of many materials such as hard plastic, fibreglass, concrete, stainless steel or carbon steel.

Requirements for potable water coatings

• Potable water coatings should not contaminate or affect the quality of the drinking water. In particular the smell or taste of water should not be affected by the coating.

• A suitable coating for potable water tanks should last with minimal maintenance for up to 25 years without problems of corrosion or water quality.