There were 18,642 households, out of which 45.3% had children under the age of 18 living with them, 66.6% were married couples living together, 12.2% had a female householder with no husband present, and 15.8% were non-families. 11.3% of all households were made up of individuals, and 3.8% had someone living alone who was 65 years of age or older. The average household size was 3.57 and the average family size was 3.83. The median price of a house in Union City is about $400,000.