Peosta has experienced a 72.6% increase in population from 2000 to 2007, making it the state's 6th-fastest growing city (with 1,000 people or more) during that period.
As of the census of 2000, there were 651 people, 223 households, and 183 families residing in the city. The population density was 482.9 people per square mile (186.2/km²). There were 223 housing units at an average density of 165.4/sq mi (63.8/km²). The racial makeup of the city was 98.92% White, 0.15% African American, 0.31% Asian, and 0.61% from two or more races. Hispanic or Latino of any race were 0.77% of the population.
There were 223 households out of which 49.8% had children under the age of 18 living with them, 75.3% were married couples living together, 5.4% had a female householder with no husband present, and 17.5% were non-families. 14.8% of all households were made up of individuals and 4.0% had someone living alone who was 65 years of age or older. The average household size was 2.92 and the average family size was 3.24.
Age/gender spread: 34.9% under the age of 18, 6.1% from 18 to 24, 38.2% from 25 to 44, 14.7% from 45 to 64, and 6.0% who were 65 years of age or older. The median age was 30 years. For every 100 females there were 95.5 males. For every 100 females age 18 and over, there were 100.9 males.
The median income for a household in the city was $56,250, and the median income for a family was $56,797. Males had a median income of $38,500 versus $23,516 for females. The per capita income for the city was $17,499. About 1.2% of families and 1.7% of the population were below the poverty line, including 1.7% of those under age 18 and none of those age 65 or over.