There are a number of code requirements that need to be met when replacing your water heater. These include things like making sure the new water heater has been certified by the National Fire Protection Association (NFPA) and following all installation guidelines. Additionally, make sure you have Schedule 80 approval before starting any work, since most water heaters need to meet this standard in order to be installed. If you need help meeting any of these requirements, please contact a licensed contractor.