Final answer:
If the regulatory authority suspends the permit to operate a kitchen due to waste water issues, a plumber should be contacted to diagnose and fix the problem.
Step-by-step explanation:
If the regulatory authority suspends the permit to operate a kitchen, it indicates that there are certain issues or violations related to waste water management. In this case, the appropriate professional to be contacted would be a plumber. A plumber specializes in the installation and repair of pipes and fixtures, including those related to waste water disposal. They can diagnose the cause of the waste water backup and take the necessary steps to fix it.