How to Check Your Showerhead’s GPM Rate

Nowadays, every shower head that is manufactured and sold in the US, whether it’s at a local Lowe’s, Home Depot or through is limited, by law, to a maximum 2.5gpm flow rate. This doesn’t mean, however, that your showerhead’s flow rate, or gallons-per-minute (gpm) usage is at or below the maximum legal threshold.

If you’re wondering what your shower head’s flow rate is, here is an easy way to check how many gallons per minutes your shower uses.

Tools you need to check your shower’s flow rate

  • A bucket or pail – preferably one that will hold up to 5 gallons of water, but definitely one that is wide enough to catch your shower’s water spray.
  • An empty 1-gallon jug – an empty milk jug will work fine.
  • Tape and/ or a marker – masking tape or even duct tape will work well, but if you don’t care about marking up your bucket or pail, a Sharpie or another type of permanent marker will be easier.
  • A stopwatch or timer – something that allows you to track seconds and minutes. Your analog wristwatch will even work so long as it has a seconds hand.
  • Optionally, you may want a helper who can either hold the bucket under the shower or monitor the timer so you can get a more-accurate reading.

Preparing to test your shower’s water usage

Before you can test how much water your shower uses, you need to mark the bucket or pail in one-gallon increments. To do this, fill your gallon-jug up with your faucet, tub or garden hose, and then dump that water into the bucket. Mark the fill level with the tape or marker (inside, but if you can see through the bucket — marking the outside would be easier). One that’s done, do not dump the water in the bucket out yet, rather fill the milk jug again and repeat the above step.

Keep filling the jug and marking the bucket until you run out of room. Once your bucket or pail is marked in one-gallon increments, you can dump the water out. If it’s summertime or you have plants, you can re-purpose the water so as not to waste it.

Checking your shower head gpm rate

Now, simply take the empty bucket into your bathroom, hold the bucket under your showerhead so that you catch all falling water, start the timer, and turn on your shower. This is where the helper comes in — in some cases it can be difficult for one person to perform these steps by themselves. After one minute passes, turn the shower off.

Now, you should have a relatively-accurate estimation of how much water your shower uses, or the gallons per minute flow rate. The amount of water in the bucket represents the number of gallons per minute that you use when taking a shower.

While US law limits the flow rate, or gpm usage rate, of shower heads manufactured and sold in the US after January 1, 1994, you are under no obligation to have a showerhead that meets those federal guidelines. Unless your state laws or local building codes say otherwise, you are free use a showerhead that works for you, regardless of its gallons per minute usage.

Not happy with the results?

If your shower head water usage is too high for your liking, we recommend checking out our low-flow showerhead comparison list. It offers a side-by-side comparison of today’s most popular shower heads, links to review along with the gallons per minute flow rates so that you can find a shower head that works for your needs.