Wainuiomata is a large dormitory suburb located in Lower Hutt within the Wellington metropolitan area of New Zealand. As of June 2025, the area has an estimated population of 20,450 and a population density of approximately 1,600 people per square kilometer.
European settlement in Wainuiomata began in the 1850s, initially driven by farming and timber-felling activities. The area experienced significant growth starting in the 1920s and saw rapid expansion following World War II. During this period of growth, it earned the nickname "Nappy Valley" due to the high concentration of families with young children.
Following a period of economic slowdown and population decline from the late 1980s, Wainuiomata has experienced a housing boom and a corresponding increase in population since approximately 2020. The suburb is also notable for being the origin of New Zealand's kōhanga reo movement.