One question that comes up often is “How do I know how many gallons per minute my well pump is pumping?”  This is crucial information when purchasing or installing water treatment systems, as they all come in different sizes and have different requirements based on your flow rate.

For example, say your well pump has a maximum flow rate of 5 gallons per minute.  This means you can fill a 5 gallon bucket in one minute.  If you choose a backwash filter system that requires 10 gallons per minute for backwash you'll find that it won't work properly, because you need a system that functions on 5 GPM.

Luckily, determining your well flow rate is easy and only takes a few minutes:

  1. Open any faucet or hose bib (a hose bib is a faucet to which a hose can be attached; you probably have one on the side of your house or in your backyard) until your well pump turns on
  2. Close the faucet or hose bib and let your pump fill your pressure tank until the pump turns off
  3. Using your 1 or 5 gallon bucket, open the faucet again and collect and measure all water discharged until your pump turns back on
  4. When the pump turns on, immediately close the faucet and start your timer
  5. When the pump turns off again, record the time it took to refill your pressure tank in seconds
  6. Divide the number of gallons collected in Step 3 by the number of seconds recorded in Step 5
  7. Multiply the number from Step 6 by 60 – this is your pump’s average pumping capacity in gallons per minute

If you cannot tell when your pump is turning on and off, you can use your pressure switch instead.   Simply locate the pressure switch and remove its cover.  [WARNING: Live voltage is under the pressure switch cover.  Please DO NOT touch any of the live electric terminals inside.]  Note that the pressure switch has four terminals that open and close as the pump runs.  When these terminals are closed together, this means the pump is running; when they are open, the well pump is off.

To make your calculations even easier, we've provided a flow rate calculator on our website.

Please send any questions or comments to support@cleanwaterstore.com, or drop us a line on Facebook.  We love to hear from you!

Gerry Bulfin

Gerry Bulfin is a licensed water treatment contractor and consultant based in Santa Cruz California and founder and owner of Clean Water Systems and Stores Inc. Gerry is a long time member of the National Ground Water Association, the American Water Works Association (AWWA) and the Water Quality Association (WQA).

Recent Posts

How Whole House Water Filters Keep Your Family Safe: A Mom’s Guide

When creating a safe and healthy environment at home, clean water is essential—especially for moms…

3 weeks ago

Why Testing Your Well Water is Essential

This brief article gives information about several common contaminants found in private wells. It should…

4 weeks ago

Top 12 U.S. Cities with the Hardest Water in 2024

Which are the U.S. Cities with the Hardest Water?  Hard water is a common issue…

2 months ago

Whole House Carbon Filters vs. Water Softeners: Which is Better for Combatting Dry Hair?

Many people are unaware that water quality can significantly affect hair and skin health. Whole…

2 months ago

Best Whole House Water Treatment for City Water

The Best Whole House Water Treatment for Homeowners on City Water in the U.S. When…

4 months ago

PFAS Treatment for Drinking Water: A Guide for Homeowners on Well Water

PFAS Treatment for Drinking Water is needed in many areas of the U.S. and Canada.…

7 months ago