Water Flow Rate Tool Guide

What this tool does – [Tool]

Source: U.S. EPA

This is a “solve-all” tool that relates the volume of water drawn, the duration of the water draw, and the flow rate. The primary expected use case is determining flow rate using a test container with a known volume and a stopwatch. The tool was developed as an aid in using the DHW Volume per Use tool when the flow rate is used and must be determined, but may also be used for more general purposes.

Calculated values

  • Draw volume – the volume of water accumulated by the end of the time interval.
  • Draw duration – the time interval of the flow.
  • Flow rate – the water flow rate.


  • Clicking the label for any input or result will cause a popup help box to appear. This help box includes the allowed and normal values (for inputs).
  • This is a “solve-all” tool. Select the radio button to the left of the label for which you wish to solve. This label will turn to blue and the input box will disappear.