Pool Pump Max Head: How Much Is Enough?

What Max Head Names in a Listing

In a pool pump listing, max head is the pump's maximum head output, stated in feet, at no flow. Head is a measure of pressure expressed as the height of a water column, and it is explained in more detail in the pool pump head article. At no flow the line is closed, so the pump produces no flow and reaches its highest head figure.

The listing states this figure as 'max head' or 'maximum head', usually beside the horsepower and flow figures. A title may state a max head figure in feet with the flow in GPM, or it may state only the flow and leave head out, which the buyer reads as 'not stated by the seller'.

The max head figure is one point on the maker's performance curve, the point where flow stops. A pump listing that repeats that figure is repeating the maker's data; the seller has not measured it. How the curve is read is the subject of the next section.

Reading a Pump Curve

A pump curve is a chart with flow in GPM on the horizontal axis and head in feet on the vertical axis. The curve is a downward line: at low flow the head is high, at high flow the head is low. The left end of the line, where flow approaches no flow, is the max head. The right end is the maximum flow at near no head.

The pump operates where its curve crosses the resistance of the pool's pad. Longer pipe runs, more fittings, a filter, a heater, and elevation differences raise the resistance, which moves the operating point up and left toward lower flow. A short, open pad moves it down and right toward higher flow. Reading the curve this way is a general explanation; it is not a sizing calculation.

Some makers publish the curve in the product page or in the manual. Hayward's homepage links a Total Dynamic Head Calculator, and Pentair's product pages list pump specifications and flow figures for each model. When a listing does not include the curve, the stated max head is the only head data the buyer can compare.

Why the Plumbing Decides the Match

Max head alone does not show whether a pump suits a pad. Two pumps with the same stated max head can have different curves: one may keep more flow at moderate head, the other may drop off quickly. The max head figure is a single point at no flow, and the operating point usually sits somewhere in the middle of the curve.

The pad's resistance comes from the pipe diameter and length, the number of fittings, the filter type, a heater if installed, and the elevation difference between the pump and the water surface. A pump with a higher stated max head has more pressure capability, but the curve shows what happens at the operating point the pad creates.

The maker's sizing page and the installation manual describe the intended plumbing for each pump model. An installer, a pool builder, or a service professional can look at the existing pad and recommend a pump whose curve covers the pad's resistance. A variable speed pump may publish a curve for each speed setting, which gives the buyer more to compare than a single max head figure.

Questions for the Maker's Sizing Page and an Installer

The maker's sizing page, such as the Total Dynamic Head Calculator linked from Hayward's homepage, asks for the pad's details and returns a pump recommendation. The buyer enters pipe length, the number of fittings, filter type, and other stated details, and the page names a pump size. This is the intended way to match a pump to a pad.

Ask an installer what head the pad produces, which pump curve covers that head at the flow the pool needs, and whether the pad needs a larger pipe, a shorter run, or fewer fittings to reduce resistance.

Before replacing a pump, check with the local building office for any equipment requirements. The local office, the utility, and the HOA may have rules the buyer must follow; this site does not state those rules.

Comparing Two Pump Listings on Max Head

When comparing pumps, treat max head as a stated figure, not a promise. The listing states the maker's number; this site compares that stated number across listings of the same speed type and pool type.

A pump with a higher stated max head and a published curve that holds flow across the middle range is a better match for a pad with long lines and many fittings. A pump with a lower stated max head and a curve that drops steeply may suit a short, simple pad. These are general comparisons of stated details, not measurements.

Read the full title: a pump may state max head, flow in GPM, horsepower (HP or THP), voltage, and pool type. The max head figure is one of several stated details; the others matter for the pad's voltage, the pump's mounting, and the filter size.

What This Site Does Not Say About Max Head

This site does not calculate turnover, total dynamic head, or a flow figure for a pool's volume. It does not match a max head figure to a pool's size or pipe length. Those numbers come from the maker's sizing page and an installer. Turnover is explained as a term elsewhere.

The site compares stated details only: stated max head, stated flow, stated horsepower, stated voltage, and the pool type the listing names. When the listing does not state a figure, the site leaves the figure out and says the seller did not state it. The Pool & Hot Tub Alliance, the industry association accredited by ANSI, maintains national consensus standards for pools and spas; this article does not restate those standards.

What to pick for your situation

Questions

What is max head on a pool pump?

Max head is the pump's highest head output at no flow, stated in feet. On the pump curve it is the left end of the line.

What does a pump curve show?

Flow in GPM on one axis and head in feet on the other. The pump operates where the curve crosses the pad's resistance.

Does a higher max head mean a better pump?

No. Max head is one point at no flow. The shape of the curve and the pad's resistance decide how the pump behaves.

How do you match a pump to your plumbing?

Use the maker's sizing page, such as Hayward's Total Dynamic Head Calculator, and ask an installer. This site does not size pumps.

Why does the site not give a head-to-pool-size match?

The site has no data for that match. The maker's sizing page and an installer provide the numbers.