Illinois Class D Water License Practice Exam 2026 - Free Water License Practice Questions and Study Guide

To determine the average system pressure at homes located 102 feet lower than a water tower situated 144 feet above the base, we can use the principle that water pressure is generated by the height of the water above the point of measurement.

The pressure due to the height of water can be calculated with the following formula:

\[ \text{Pressure (psi)} = \frac{\text{Height (ft)} \times 0.433}{1} \]

Here, 0.433 psi represents the pressure exerted by a column of water per foot in a water system.

First, we find the effective height above the homes:

1. The height difference between the water tower and the homes is 102 feet.

2. Therefore, we need to consider the height of the water tower minus the height of the homes:

\[

\text{Effective height} = 144 \text{ ft} - 102 \text{ ft} = 42 \text{ ft}

\]

Now we calculate the pressure at that effective height:

\[

\text{Pressure (psi)} = \text{Effective height (ft)} \times 0.433

\]

Substituting the effective height into the