Conservative estimates indicate the city of San Marcos's population could reach as high as 87,759 by 2030.
The city's Planning and Zoning Commission on Tuesday was presented with San Marcos's annual population report, which included statistics such as the city's current population, future projected population and number of new student housing.
By the city's calculations, San Marcos had 64,589 residents as of Jan. 1.
The city uses a housing unit method to calculate its population. The 2010 U.S. census population is used as the base population, and then the city considers single-family and multifamily units that have received a certificate of occupancy and multiplies that by the occupancy rate and persons per household, according to Amanda Hernandez, development services manager.
The city also considers population increases based on areas that have been annexed and the number of university/rent-by-the-bedroom units that have opened in the past year.
San Marcos Planning Director Shannon Mattingly said the city uses these numbers consistently when applying for grants.
Based on 2017's growth rate of 2.59 percent, the city anticipates adding 23,170 people in the next 12 years.
Planning and zoning commissioners were also told that number could reach 108,362 if the city calculates the population growth projections using a growth rate of 4.41 percent, the average rate the city has grown since 2010.
"I would anticipate something closer to the 2017 growth rate numbers continue," Mattingly said.
The city also analyzed the number of units, or rooms, the city has added over the last few years that are considered Texas State University housing or rent-by-the-bedroom units.
Mattingly said these numbers are based on the university's current student population, its projected enrollment growth, the number of dorm rooms slated to be added and the number of rent-by-the-bedroom units anticipated to come online.
"We have ongoing discussions with [Texas State] about the populuation, but this is basically what the estimated growth is," Mattingly said. "It’s not really a perfect science."
The university had 38,666 students enrolled in 2017, according to the Texas Higher Education Coordinating Board.
By 2027, 46,444 students are projected to be enrolled based on an annual overall projected growth rate of 1.7 percent, according to the university's 10-year master plan.