Rhode Island Journeyman Plumber Practice Exam 2026 - Free Journeyman Plumber Practice Questions and Study Guide

The maximum water temperature setting for a tankless heater or domestic hot water heater is typically 210 degrees Fahrenheit. This setting is largely in place for safety reasons, as higher temperatures can increase the risk of scalding when hot water is used for bathing or other applications.

There are several reasons why 210 degrees is the chosen limit. Firstly, it balances the need for hot water in applications while minimizing the risk of burns. Most plumbing codes and manufacturer guidelines recommend not exceeding this temperature in residential settings to ensure user safety. Exceeding this temperature can also have negative impacts on plumbing materials, increasing the potential for damage or degradation of pipes and fixtures over time.

In contrast, temperatures beyond 210 degrees, such as 220 degrees or higher, can be excessive for everyday use and are generally considered unsafe for residential water heating. Overall, maintaining a maximum setting of 210 degrees helps ensure that the water heater operates securely and efficiently while also protecting users from serious burns.