Determine Flow Rate for Wells with Pressure Tanks

It is easy! All you need is a 1 or 5 gallon bucket and a watch or clock! It takes just a few minutes. Just follow these steps:

1. Open any hose bib or faucet until pump turns on.

2. Close hose bib or faucet and let pump fill up pressure tank until it turns off.

3. Using a 1 or 5 gal. bucket, open faucet, collect and measure all water discharged until pump turns on.

4. When pump turns on, immediately close faucet and start timing pump cycle.

5. When pump turns off, record pump cycle time to refill pressure tank in seconds.

6. Divide the number of gallons collected in Step 3 by the number of seconds in Step 5.

7. Multiply the answer from Step 6 by 60.

8. The answer in Step 7 is the average pumping capacity of the pump in gallons per minute (GPM).

Example: Number of Gallons collected during draw-down of pressure tank (Step 3) =

Number of Seconds in pump cycle to refill pressure tank (Step 5) =

Gallons Per Minute (GPM) = (Gallons collected / seconds in cycle) x 60"

GPM =

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