How to Calculate the GPM of your Faucet or Showerhead
Becoming a water wise consumer is a matter of reducing excessive water consumption. Your water meter is a helpful tool to monitor your monthly water consumption. Another good starting point to residential water conservation is the replacement of water wasting faucets and showerheads with their water efficient counterparts.
The volumetric flow rate of your shower head or faucet is measured in gallons per minute (GPM). The Federal Energy Policy Act of 1992 required all faucets and showerheads to have a water efficient flow rate of no more than 2.2 GPM at 60 PSI. Yet toilets, faucets and shower heads and other fixtures bought and installed before 1992 waste as much as 10 GPM. The following guiding steps are provided by professional plumbers to calculate the GPM of your water fixtures:
Position a container under faucet or shower head
Turn on fixture for 10 seconds and collect water in container
Measure the quantity of water collected in 10 seconds and convert units to gallons
Multiply the gallon measurements by 6 to get the GPM value.
Plumbing fixtures with flow rates greater than 2.2 GPM will need to be replaced with low flow units that will cut down your water usage by as much as 40%. The reduction in your water consumption will show up nicely in lower than average water bills. The following table summarizes how much water you save with water efficient fixtures.
|Fixture||GPM of regular fixture||GPM of low flow fixture||Water Saving Tips|
|Shower||7||2.5||Take shorter showers|
|Bath||28-36||14-18||Don't fill a tub to its brim|
|Running Faucet||3||2-2.5||Turn off water flow when soaping hands, dishes, or brushing teeth|
|Washing Machine||40-55||18-25||Wash full loads|
|Toilet||6||1.6||Don't flush diapers, hygiene products, and other non-breakable waste|
|Brushing teeth with running water||3||1.5||Turn off water flow when brushing teeth. Turn on water for rinsing only.|
|Hand dishwashing||3||2.2||Fill sink with water to rinse.|