Atwater, CA has a population of 28,906 and is the 1,484th largest city in the United States. The population density is 4,726 per sq mi which is 1746% higher than the California average and 5116% higher than the national average. The median age in Atwater is 30 which is approximately 16% lower than the California average of 36. In Atwater, 51% of the population over 15 years of age are married, 52% speak English and 42% speak Spanish. 62% of Atwater residents were born in California, 14% were born out of state, 2% were born outside of the United States and 22% were foreign born.