The Ministry of Health advises that it's prudent to assume that houses constructed during the 1980s or earlier, as well as commercial buildings of the same era, have likely been coated with lead-based paint at some point. This precautionary standpoint extends to New Zealand's contemporary practices, as the use of lead-based paint is now extremely restricted due to its potential harm to adults, children, and the environment. In preceding decades, however, lead-based paints were commonplace. The challenge lies in the inability to discern the presence of lead in the paint on various surfaces of your residence, such as walls and ceilings. This uncertainty remains even when more recent paint layers have been applied, as underlying strata of older paint, some of which might contain lead, could be present.