Find your horsepower in the row, then read across. Total head is the lift from the pumping water level to the discharge, plus the pressure you want at the tank (2.31 ft for every PSI), plus friction in the drop pipe.
Total head in feet · curves end at 24.5 GPM
| HP |
0 GPM (Shut-off) |
5 GPM |
12.5 GPM |
17.5 GPM |
22.5 GPM |
| 1/2 HP |
152 ft |
142 ft |
110 ft |
73 ft |
23 ft |
| 3/4 HP |
211 ft |
200 ft |
156 ft |
104 ft |
34 ft |
| 1 HP |
299 ft |
286 ft |
223 ft |
150 ft |
51 ft |
| 1 1/2 HP |
367 ft |
351 ft |
274 ft |
183 ft |
62 ft |
| 2 HP |
519 ft |
499 ft |
389 ft |
261 ft |
89 ft |
| 3 HP |
645 ft |
615 ft |
482 ft |
326 ft |
110 ft |
| 5 HP |
1084 ft |
1026 ft |
814 ft |
559 ft |
188 ft |
Read from the published curve in the Pumps by Baker catalog (Sept 2025, rev 3/26), p. 74, digitized and rounded down, at the flows nearest 20%, 50% and 75% of the curve’s 24.5 GPM end. 0 GPM is the printed shut-off. For the 1/2 HP curve, the published curve and A.Y. McDonald’s printed output tables disagree by about 16 ft on average; the head figures are read from the curve, and the output tables below are the printed figures. The last column is the last flow every curve reaches; the curve ends are named in the table title.
Output in GPM at 30 PSI (switch cut-in), by depth to water · 1/2–3/4 HP
| HP |
25 ft |
50 ft |
75 ft |
100 ft |
125 ft |
| 1/2 HP |
15.4 |
11.7 |
— |
9.1 |
6.1 |
| 3/4 HP |
18.6 |
16.5 |
14.2 |
11.3 |
7.3 |
Output in GPM at 50 PSI (switch cut-out), by depth to water · 1/2–3/4 HP
| HP |
25 ft |
50 ft |
75 ft |
100 ft |
125 ft |
| 1/2 HP |
— |
— |
6.6 |
— |
— |
| 3/4 HP |
14.6 |
11.8 |
8.1 |
— |
— |
Output in GPM at 30 PSI (switch cut-in), by depth to water · 1–5 HP
| HP |
25 ft |
50 ft |
100 ft |
150 ft |
200 ft |
250 ft |
300 ft |
| 1 HP |
20.6 |
19.4 |
— |
13.1 |
8.2 |
— |
— |
| 1 1/2 HP |
21.4 |
20.4 |
18.3 |
15.8 |
12.9 |
9.1 |
— |
| 2 HP |
— |
21.8 |
20.4 |
18.9 |
17.3 |
15.5 |
13.5 |
| 3 HP |
— |
22.4 |
21.3 |
20.2 |
19.0 |
17.7 |
16.3 |
| 5 HP |
— |
23.3 |
22.7 |
22.2 |
21.6 |
20.9 |
20.3 |
Output in GPM at 50 PSI (switch cut-out), by depth to water · 1–5 HP
| HP |
25 ft |
50 ft |
100 ft |
150 ft |
200 ft |
250 ft |
300 ft |
| 1 HP |
18.2 |
16.8 |
13.4 |
8.7 |
— |
— |
— |
| 1 1/2 HP |
19.5 |
18.4 |
16.0 |
13.2 |
9.5 |
— |
— |
| 2 HP |
— |
20.5 |
19.0 |
17.4 |
15.7 |
13.7 |
11.3 |
| 3 HP |
— |
21.4 |
20.3 |
19.1 |
17.8 |
16.4 |
14.9 |
| 5 HP |
— |
22.8 |
22.2 |
21.6 |
21.0 |
20.3 |
19.7 |
Output tables as printed in the Pumps by Baker catalog (Sept 2025, rev 3/26), pp. 73-74, at the 30 and 50 PSI rows. Riser-pipe friction is not included (manufacturer note): add it for long or small drop pipe. — marks a point A.Y. McDonald does not print for that horsepower. Left blank as apparent misprints (printed out of sequence; confirm with the factory): 1/2 HP, 30 PSI, 75 ft: printed 5.8; 1/2 HP, 50 PSI, 25 ft: printed 7.0; 1/2 HP, 50 PSI, 50 ft: printed 9.5; 1 HP, 30 PSI, 100 ft: printed 6.6.
Best operating range: the published curve shades the most efficient operating range for each model; the catalog prints no figures for it. The curve is in the image gallery.
