Which material cannot be used to construct cesspools?

Cesspools are underground reservoirs for collecting liquid waste, and the materials used in their construction must be durable, resistant to corrosion, and able to withstand the harsh environment that comes with holding sewage and wastewater. Redwood, while it is a naturally durable wood, is not suitable for constructing cesspools due to its potential for decay over time when in constant contact with moisture and sewage.

Concrete, fiberglass, and steel are all viable materials for cesspool construction. Concrete offers the strength and permanence needed for such installations, fiberglass is resistant to corrosion and can be shaped into the required forms, and steel, when treated or galvanized, can also provide sufficient durability against the elements. However, redwood does not have the longevity or resilience required, making it an unsuitable choice for this application.