Recirculation Pump

A recirculation pump sits on the hot water line—usually near the water heater or at the furthest fixture—and pushes heated water back through the return line to the heater. This keeps the pipes hot at all times, so when you turn on a tap, hot water arrives in seconds instead of minutes. No need to run water while waiting for it to heat up.

These pumps run on demand (triggered by a button or timer) or continuously, depending on the setup. Most residential systems use a 1/6 or 1/4 HP pump with a thermostatic check valve to prevent backflow. Installation requires a dedicated return line running parallel to the main supply—a retrofit that's more work than a new build, but worth it in houses with long hot runs to master baths or kitchens far from the heater.

In the field, the pump reduces water waste and makes occupants happy. The downside: it costs more to install, adds to the water heater's workload, and burns energy to run. Check local code—some jurisdictions require them in commercial buildings or large homes; residential is usually optional but increasingly expected on high-end work.