True or False: The walls and bottom of poured-in-place septic tanks must be reinforced.

The correct answer is that the walls and bottom of poured-in-place septic tanks must be reinforced. This is essential to ensure the structural integrity and durability of the tank. Poured-in-place tanks are typically made from concrete, which, while strong in compression, can be vulnerable to tensile stresses and cracking if not properly reinforced.

Reinforcement provides additional support, helping to maintain the shape and strength of the tank under soil pressure and external loads. Without adequate reinforcement, the tank could fail, leading to leaks or structural collapse, which could pose significant environmental hazards.

Though some options may suggest that only specific parts of the tank require reinforcement, it is standard practice to reinforce both the walls and the bottom to ensure comprehensive strength throughout the structure. This practice also helps in prolonging the lifespan of the septic system and in maintaining proper function.