Exam math · Hydraulics
Pressure and head
Converting between water column height and pressure at the bottom of it.
The formula
One foot of water column exerts 0.433 psi; one psi supports 2.31 feet of water.
The unit trap
The two constants are reciprocals, and the exam happily accepts the answer computed with the wrong one. Height to pressure uses 0.433; pressure to height uses 2.31.
Worked practice example
A practice tank with water 100 feet above a gauge reads about 43.3 psi. (Invented numbers.)
On exam day
A formula and conversion table is provided with the standardized exam; the official version is published by the exam provider at gowpi.org. These pages teach the concepts in our own words so the sheet on the desk reads as a reminder, not a puzzle.
The rest of the math
| Volumes | Tank volume |
| Volumes | Pipe and cylinder volume |
| Flow | Flow and velocity |
| Flow | Detention time |
| Treatment math | Chemical dosage |
| Treatment math | Percent strength and dilution |
| Treatment math | Removal efficiency |
| Hydraulics | Pump and horsepower math |
| Foundations | The conversion backbone |
| Foundations | Averages and loading rates |
| Foundations | The formula-first method |
The operator math sheet
One printable page: the exam format, the formula-first drill method, and the unit-conversion discipline that decides the math questions. Free.
No spam. One useful sheet and occasional notes.