As of the census of 2010, there were 12,065 people, 5,125 households, and 3,023 families residing in the city. The population density was 6,721.0 people per square mile (2,588.0/km²). There were 5,311 housing units at an average density of 2,958.6 per square mile (1,139.2/km²). The racial makeup of the city was 80.03% White, 1.46% African-American, 1.38% Native American, 6.09% Asian, 0.18% Pacific Islander, 7.80% from other races, and 3.06% from two or more races. Hispanic or Latino of any race were 22.62% of the population.
There were 5,125 households out of which 28.7% had children under the age of 18 living with them, 39.7% were married couples living together, 13.8% had a female householder with no husband present, and 41.0% were non-families. 31.4% of all households were made up of individuals, and 9.9% had someone living alone who was 65 years of age or older. The average household size was 2.35, and the average family size was 2.97. In the city, the population was spread out with 24.9% under the age of 18, 12.8% from 18 to 24, 31.6% from 25 to 44, 18.2% from 45 to 64, and 12.5% who were 65 years of age or older. The median age was 31 years. For every 100 females, there were 95.0 males. For every 100 females age 18 and over, there were 91.4 males.
The median income for a household in the city was $33,750, and the median income for a family was $38,468. Males had a median income of $31,054 versus $25,195 for females. The per capita income for the city was $16,801. About 9.2% of families and 11.2% of the population were below the poverty line, including 16.5% of those under age 18 and 3.7% of those ages 65 or over.
Federal Heights is the home of a major water park named Water World.