Humber/Ontario Real Estate Course 3 Exam Practice

What is the most probable cause of contamination in a water well discovered by a property owner?

1. The well is too shallow; i.e., more than 20 feet but less than 40 feet in depth.

2. The well is drilled with small diameter piping.

3. Surface water contamination leaking into the well due to drainage problems.

4. Openings to the well from the outside are sealed.

5. The well is more than 60 feet deep.

6. The well is located near a chemical spill.

The correct answer is: Surface water contamination leaking into the well due to drainage problems.

Contamination in a water well is often attributed to surface water infiltrating the well system, especially in cases where drainage issues exist. When there are inadequate barriers or safeguards in place to prevent surface water—which can carry pollutants such as fertilizers, pesticides, or even bacteria—from entering the well, contamination is likely to occur. This can happen in situations where the well is improperly sited or maintained, allowing surface runoff to reach the water supply. Surface water is more likely to introduce contaminants into shallower wells compared to deeper wells, as they are closer to potential sources of pollution. Additionally, drainage problems can exacerbate this issue by causing water to pool or flow in ways that direct contaminants toward the wellhead instead of away from it, making it crucial for property owners to manage drainage effectively to mitigate such risks. While there are other factors that could contribute to contamination risks, the direct link between surface water and well contamination through poor drainage highlights why this choice is considered the most probable cause. In contrast, factors like the depth of the well or its diameter may influence overall water quality and flow but do not specifically address the issue of surface contamination in the same direct manner.