In the past iron coated in a protective zinc alloy (galvanised steel) was the steel of choice of roofs, sheds and the iconic rainwater tank found in the Australian outback. Today, traditional corrugated galvanised steel tanks also compete against more modern steels such as ZINCALUME® and AQUAPLATE® as well as different grades of stainless steel.
While rainwater tanks are found in these other steels often considered to be better quality and more corrosion resistant, heavy duty galvanised steel tanks that are more thickly coated are still a valid option today. Furthermore, they will last just as long, are often less prone to moisture due to their thick zinc coating and length of warranties are often similar.
It is also important to understand that modern steels cannot come into contact with galvanised steels or vice-versa. So if your roof, gutters or connecting pipes are of one quality metal, then it is good to ensure your rainwater tank if steel is of the same quality metal. There should be no mixing of any ZINCALUME® steel with galvanised steel or vice-versa.
Today, galvanised steel tanks come with an inner poly lining. This provides additional protection to the steel tank from the rainwater stored within causing rust and corrosion. It also helps to prevent leaks at welded joints, which can be a weak point in steel tanks and a cause for water leaks. The inner poly lining in galvanised steel tanks also stops zinc leaching into your rainwater which can give your water an unpleasant metallic taste.