School District License
Yes in the state of TX, since 1984 anyone doing pest control on school property must have a license. In 1995, the TX Legislature enacted a law requiring all public schools to adopt integrated pest management. The bottom link will take you to the actual rules that is regulated by the TX Dept of Agriculture.
However, if you are having trouble with mice, rats, ants, cockroaches in your classroom, you should find out who your district IPM Coordinator is. Every school district in the state must have one, the person can assist you with your pest problem.
This link http://schoolipm.tamu.edu/ can explain more about school IPM in TX. Your question actually came to someone who helps schools with their IPM Programs,so do not hesitate to ask me more questions. Have a good day