San Marcos experienced a period of growth from 1956 onward, when the first water from the Colorado River arrived. Several small businesses were founded and the population rapidly increased to 2,500. San Marcos became an incorporated city on January 28, 1963. In the 1970s, San Marcos was flourishing as the third fastest-growing city in the state, and had a population of 17,479 by 1980. The population continued to boom over the next two decades, surpassing 30,000 in 1990 and nearing 85,000 by 2010.