Water Well Flow & Yield Test?

Anyone have a written procedure for doing flow and yield tests on water wells? I just bought a Toro flow and pressure gauge so I wouldn’t have to do the tests with a graduated cylinder. Having a hard time trying to find a concise explanation on how to use these gauges and the calculations.

Any help would be appreciated.


I do my set up when i first get to the home.
I hook up a hose to the tank “T” spigot and run the hose as far from the house, septic, well as possible.
Then I flush out the line for a few minutes while I check the cut in/out pressure for the switch.
I then hook up the Toro to the hose end and adjust the flowrate on the Toro until it hits that midpoint pressure (i.e. 40 @ 30/50) and record it then let it run.
I start my normal inspection and check back at the tank every once and awhile.
I then document the flowrate at the end of the HI (usually 3-4H) and report as “8gpm @ 40psi for 180min”.

By the way, be very careful with the Toro, they can stop working all of a sudden so I always bring my “measured” bucket and stop watch with me.

When it stops showing flowrate, I take it all apart, clean etc.


I have a similar gauge that I utilize for well water testing.

With this hooked up to the closet spigot from the main water supply area, with the water “ON” at full blast, the left gauge will tell you the GPM (Gallons Per Minute) and the right side tells you the (PSI) water pressure coming from the well.

If you ran a spoggot flat open for 180 minutes at my house, you’ve just conducted an invasive test, because my well will collapse in and you’ll have thick mud coming out of the faucets.