In the United States, the standard showerhead has a ½ inch female NPT thread.


In the United States, the Energy Policy Act of 1992 set a limit of 2.5 gallons per minute. In 2010, the maximum permitted flow rate was reduced to 2 gallons per minute (7.6 liters per minute).

for further reading

The Fed's rulings and reasoning can be examined at:

home | home index | search | to contact Sizes drawing of envelope | acknowledgements | help |


terms of use