There were 7,626 households out of which 40.1% had children under the age of 18 living with them, 57.2% were married couples living together, 13.0% had a female householder with no husband present, and 25.7% were non-families. 22.7% of all households were made up of individuals and 11.2% had someone living alone who was 65 years of age or older. The average household size was 2.82 and the average family size is 4.
In the city, the population was spread out with 31.0% under the age of 18, 11.5% from 18 to 24, 26.0% from 25 to 44, 18.0% from 45 to 64, and 13.5% who were 65 years of age or older. The median age was 31 years. For every 100 females there were 91.7 males. For every 100 females age 18 and over, there were 86.7 males.
The median income for a household in the city was $31,551, and the median income for a family was $35,215. Males had a median income of $26,434 versus $19,888 for females. The per capita income for the city was $13,791. About 15.0% of families and 19.1% of the population were below the poverty line, including 25.1% of those under age 18 and 14.8% of those age 65 or over.
The 1992 Steve Martin film Leap of Faith was partially filmed on location in Plainview. Until 2016, the downtown water tower bore the name and mascot of the fictional town in which the movie is set: The Rustwater Bengals. The Quick Lunch Diner, where several scenes were filmed, is now closed, and the site is now home to the Broadway Brew.
In the eighteenth episode of the second season of Vice Plainview was featured as a ghost town in a feature called "Deliver Us from Drought".
On February 11, 2009, the Texas Department of State Health Services ordered the cessation of operations and full recall of all products produced by a Plainview-based peanut processing facility owned by Peanut Corporation of America, following the discovery of "dead rodents, rodent excrement and bird feathers in the plant," and revelations that the plant had operated without state licensure or inspection. The plant had voluntarily suspended operations one day earlier, and was not linked to the salmonella outbreak that had forced the shutdown of other PCA plants.
The largest employer was a Cargill beef processing plant, mothballed on February 1, 2013 due to lack of incoming animals from the local area due to the 2010–2012 Southern United States drought. Closure of the plant created a crisis in Plainview as an annual payroll of $15.5 million was lost and many of the 2,300 employees and their families relocated after being laid off.