Use this free well pump sizing calculator to find your total dynamic head and the Grundfos solar or AC submersible pump that fits your well. No signup needed.
How to size a well pump
Start with total dynamic head (TDH): the pumping water level, plus the rise from the wellhead to the tank or house, plus the pressure you need (psi x 2.31), plus friction losses in the pipe. Then pick a pump rated for the flow you need at that head.
Shop solar well pumps and well pump accessories. Powering the pump from solar and batteries? Size the rest of the system with our off-grid solar and battery calculator.
Frequently asked questions
What is total dynamic head (TDH)?
Total dynamic head is the total lift a pump has to overcome, in feet. It adds the pumping water level, the vertical rise from the wellhead to the tank or house, the pressure you need at the end (converted to feet), and friction losses in the pipe.
How do I convert psi to feet of head?
Multiply psi by 2.31. A pressure tank that shuts off at 60 psi adds about 139 feet of head.
What size well pump do I need for a house?
A typical home uses 8 to 12 gallons per minute. For example, a 100 ft water level, a 10 ft rise to the house, 100 ft of pipe and a 40/60 pressure tank add up to about 259 ft of total dynamic head, so you need a pump rated for your flow at that head.
Can a solar well pump run without batteries?
Yes. Grundfos SQFlex pumps run directly from solar panels (30 to 300 VDC) and pump while the sun shines, usually into a storage tank. With the IO 101 switch box they can also run from a generator.
Should I choose a solar direct pump or an AC pump?
Solar direct pumps suit remote tanks, livestock and cabins where you can store water during the day. AC pumps like the Grundfos SQ series run from an inverter and batteries, a generator or the grid, and supply a pressure system on demand.