Position the 5-gallon bucket beneath the faucet. Buckets with marks on the side indicating the volume are available from most hardware stores.
Turn the water on at the same time as you activate the stopwatch. Stop the watch when the water level reaches the 5-gallon mark.
Multiply the minutes by 60 and add to the seconds portion of the time measurement to determine the total number of seconds that passed while filling the bucket.
Divide the total seconds by 5 and then again by 60 to arrive at the GPM calculation.
Things You Will Need
- 5-gallon bucket
- If you are unable to locate a 5-gallon bucket with marks on it to indicate the volume, use a 5-gallon, plastic gas can which always comes with a "Full" mark on the side. You can use any bucket or container desired as long as the container has accurate marks indicating the total volume, no matter what the volume is. Divide the total seconds by the total volume of the container and then divide by 60.