SAN DIEGO (FOX 5/KUSI) -- Representatives with the Centers for Disease Control and Prevention (CDC) will be going door-to-door in the South Bay Thursday to conduct a survey. The main topic of the survey is delving into impacts from the Tijuana River Valley sewage crisis, an issue that has been plaguing local communities for some time. For years, the river, which also drains into the Pacific Ocean, has been carrying raw sewage and other potentially dangerous toxins that come from Mexico. Federal health officials launched the new study, with many hoping it will help address the ongoing issue. As part of the efforts, thousands of residents may be selected to participate in interviews about their health. The CDC is working with San Diego County officials to conduct what has been dubbed the Community Assessment for Public Health Emergency Response (CASPER). The assessment includes finding out what residents been experiencing. This comes as many say their families are getting sick because of the contaminants that are believed to be in the water and air. The survey is expected to last about 15 minutes and will be in-person, voluntary and anonymous. According to the CDC, a total of 210 interviews will be conducted, which equals about seven random households per block. Health officials are encouraging residents selected for interviews to participate. The information gathered will help assess needs and proper resources.