i had to come to the comments to make sure I wasn't the only one...

@@bouy33 Ok, glad to see I wasn't the only one on this. I checked the math, then decided to check the comments. Thank you.

Thanks! :)

Thanks Robert! That video has been on our list for a while, but we haven't had time to shoot it properly. Hopefully towards the end of summer we'll get a chance!

Ben, give us a call or send this in an email over to us: 855.329.4519 or Customer.Service@Rcworst.com

Use 60s / 1min and cancel the units. (52gal / 25s) * (60s / 1min). Cancel the seconds leaves you with 52 * 60 / 25 gpm.

Put injection system downstream of pressure tank

You are calculating the flow rate of the pump in GPM (gallons per minute)... and doing that by timing how long it takes for the pump to refill the pressure tank with a known volume of water. You want to be sure no fixtures are using water during the test (like a washing machine or flushed toilet). If you don't know the "drawdown" then you can measure it. I suggest you measure it yourself even if the drawdown is provided on a document, because the drawdown is dependent on your 40/60 cut in and cut out being set exactly at those PSI values like they were at the pump manufacturer's when they calculated the drawdown. It is simple to measure the drawdown... and do your stopwatch work at the same time. Get a 5 gallon bucket and empty 5ea one gallon jugs of water into it... mark the 5 gallon water level on the 5 gallon bucket with a marker. Empty the bucket. Get your stopwatch ready. Be sure the washing machine isn't running or anything else that will use water. Open a spigot and let the water run onto the ground until the pressure gets low enough for the pressure switch to cut in (turning on the well pump). Turn off the spigot and start the stopwatch at the same instant in time that the pressure switch cuts in (watching the pressure gauge will help, just as Mr Worst noted... as the pressure gets close to 40psi then shut the spigot down to a very small flow so you can turn it immediately off when the pressure switch cuts in). Allow the pressure tank to fill until the pressure switch hits the cutoff value (60 psi in the example) and stop the stopwatch at the instant the pressure switch cuts off (the pump stops). Remember/write down the minute(s) and seconds shown on your stopwatch (this is the time it took to fill the pressure tank with a certain volume of water). You are done with the stop watch. Now let's determine what the volume of water was; Fill the bucket to the 5 gallon mark, shut off the spigot, empty the bucket, fill the bucket again, etc... as many times as needed until the pressure switch kicks back on at the cut in value (40psi in this example). Be sure to shut the spigot off right when the pressure switch kicks on. You are done with the pressure tank. Now measure how many gallons of water are in the partially filled 5 gallon bucket... by pouring the water into 1 gallon jugs... add that number of gallons to the previously emptied full 5 gallon buckets and you know how many gallons were emptied from the pressure tank before the well pump kicked on. This is the volume of water we were looking for, and is termed your "drawdown". Now you know the number of gallons pumped in a certain period of time... in other words you now know the gallons per time (gallons/time). Just adjust the time you measured into minutes (for example, 2 mins 30 seconds = 2.5 minutes). Now divide the gallons that went into the bucket by the minutes of time that elapsed and you have the gallons per minute (GPM) that your well pump is pumping. So if 23.5 gallons were pumped in 2.5 minutes (23/2.5) then the well pump would be producing 9.4 GPM.

At 3:50 we cover it, but I agree that we should have mentioned it sooner in the video. I appreciate the input!

Why does it need to be open in the first place?

G P , to drop pressure and get to the pump to kick on.

@@mattdeloff4348 OK, thank you. If I simply add a 2nd pressure tank do both tanks have to be sized exactly the same?

You are correct, we had it flipped. Good catch!

I am not the best at math the weekend after Memorial Day. I'm sure you see I did get the right answer, just setup the formula a little goofy. :)

Dave, regardless of how deep your well pump this method works. Water does not escape the system and thus must all pass through the tank. This method is best applied when trying to determine a rough nominal flow rate.

@@chrisworst8353 Chris, If you were buying a home with a well, are you advising to use this method to calculate well yielding when in fact the well test should be over a period of time? Are there not variables one should be aware of when calculating available water in a well?

@@amyogren3326 The method described in this video is to determine your GPM more or less for equipment sizing, not well yield. Well yield is a much more complicated topic that put simply, the more critical the water supply, the more in depth productivity test you might consider. This might be a good topic for me to do a discussion video on.