Head height is the vertical lift a pond pump must overcome to move water to its discharge point. The higher the lift—and the more resistance in the plumbing—the lower the pump’s actual flow.
What head height means
Head height is the vertical distance a pond pump must move water from the pond’s water surface to the point where the water exits, such as a waterfall outlet. It is usually expressed in feet. The greater the height, the more work the pump must do and the less water it can deliver.
For a submerged pump sending water to an open outlet, measure from the pond’s normal water level—not from the bottom of the pond or the pump’s position—to the highest point the water must reach. The pump’s depth below the surface generally does not add to the vertical lift in this setup.
Pumps with a published flow curve for higher lifts
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Maximum head is not the working flow
A pump’s maximum head rating is the greatest height it can push water under the conditions specified by its manufacturer. At or near that limit, flow may be very low or stop altogether. It does not mean the pump will deliver its advertised flow rate at that height.
Check the pump’s flow-versus-head chart, if available. Find the head height for your setup on the chart and use the corresponding flow estimate. If the chart only lists maximum head and a flow rate at zero head, those figures describe different operating conditions; neither tells you the exact flow at your installation height.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product.
Account for tubing and fittings
The vertical lift is only part of the resistance water encounters. Long or narrow tubing, bends, valves, filters, and UV clarifiers can reduce flow too. This resistance is sometimes described as friction loss or additional head.
To choose a pump:
Measure the vertical rise from pond water level to the discharge point.
Note the tubing’s inside diameter, length, and routing, including sharp bends.
Include inline equipment and check its instructions for flow or pressure requirements.
Compare the complete setup with the pump’s flow chart, then check that the resulting flow suits the feature or equipment you are supplying.
Do not assume that a larger pump will solve every low-flow problem. Confirm that the tubing, filter, and other equipment can handle the pump’s output, and follow their manufacturers’ guidance.
Use head height to compare pumps
When comparing pumps, look for the flow rate at your estimated operating head—not just the largest flow number on the package. A pump with a higher maximum head may be a better fit for a tall waterfall, but its curve and your plumbing determine the actual delivery.
If a pump must operate close to its maximum head, choose a model whose published performance supports your required flow at that height. If no performance chart is available, ask the manufacturer for the expected flow under your setup rather than relying on the maximum-head figure alone.
FAQ
Do I measure head height from the pond bottom or the water surface?
For a submerged pump feeding an open outlet, measure vertically from the pond’s normal water surface to the discharge point. The pump’s depth below the surface generally does not count as additional lift.
Does a pump produce its rated flow at maximum head?
Usually not. Maximum head is the limit the pump can reach, where flow may be very low or stop. Check the manufacturer’s flow chart for the expected flow at your operating head.
Can tubing change the effective head a pump must overcome?
Yes. Narrow or long tubing, bends, valves, and inline equipment create resistance and can reduce flow. Include them when selecting a pump.
