Massachusetts Plumbers Journeyman Practice Exam

How thick should the concrete wall be for constructing sumps and tanks for sewage?

1. 1 inch

2. 2 inches

3. 3 inches

4. 4 inches

The correct answer is: 3 inches

The recommended thickness for concrete walls in the construction of sumps and tanks designed to hold sewage is generally around 3 inches. This thickness provides a balance between structural integrity and weight, ensuring that the tank can withstand the pressure exerted by the sewage inside. Additionally, a thickness of 3 inches helps protect against potential leaks and reinforces the overall durability of the tank or sump in various environmental conditions. Thinner walls, such as 1 inch or 2 inches, may not provide the necessary strength or durability to accommodate the weight and pressure of the sewage, increasing the risk of structural failure. While 4 inches may seem like a robust option, that could be unnecessarily heavy and more costly than required for typical applications, potentially leading to inefficient usage of materials. Therefore, 3 inches is often considered the optimal standard in practice.