purpose The iron pipes used for gas, greenhouse and heating are also galvanized pipes. As water pipes, galvanized pipes produce a large amount of rust and scale in the pipes. The yellow water not only pollutes sanitary ware, but also mixed with bacteria breeding on the unsmooth inner wall. Corrosion causes the content of heavy metals in the water to be too high, which seriously endangers human health. In the 1960s and 1970s, developed countries in the world began to develop new pipes, and galvanized pipes were banned one after another. China's Ministry of construction and other four ministries and commissions have also made it clear that galvanized pipes have been banned since 2000. Galvanized pipes are rarely used for cold water pipes in new communities, and galvanized pipes are used for hot water pipes in some communities.