Tumwater is located in Thurston county Washington with a geographic area of 17.5 square miles. The total population in Tumwater is 23,390 with 47.3% male and 52.7% female. Children under age 5 represent 5.2% of the population, under age 18 equal 21.9% of the population and over age 65 is 11.5% of the population. The median household income is $76,676, per capita income is $35,917. There are a total of 9,272 housing units with 57.3% owner occupied. Education includes 13.7% of residents that are high school graduates and 39.8% with a bachelor's degree or higher. The average temperature in Tumwater in the summer is 61 degrees, and in the winter 42 degrees.