There were 21,258 housing units at an average density of 1,091.9 per square mile (421.6/km2), of which 20,433 were occupied, of which 13,580 (66.5%) were owner-occupied, and 6,853 (33.5%) were occupied by renters. The homeowner vacancy rate was 1.5%; the rental vacancy rate was 5.3%. 46,272 people (66.6% of the population) lived in owner-occupied housing units and 22,726 people (32.7%) lived in rental housing units. As of 2019, the median price of a house in Union City is between $800,000 and $1,000,000.