Concrete or Plastic? Choosing the Right Tank for Your Mobile Home

When it comes time to install a new septic system, the first question you will face is: "What should the tank be made of?" In the Gulf Coast, both concrete and polyethylene (plastic) tanks are popular choices, but they behave very differently in our local soil. This 1,000-word guide breaks down the durability, cost, and installation requirements of both materials to help you make an informed choice.

Concrete: The Heavyweight Champion

Concrete tanks have been the industry standard for decades. They are incredibly durable and can last 50+ years. In Mobile, where we have shifting clay soils, the weight of a concrete tank is actually a benefit—it is very unlikely to "float" out of the ground during a flood. However, concrete is porous and can eventually crack or corrode if the tank’s pH isn’t balanced.

Plastic: The Modern Challenger

High-density polyethylene tanks are becoming more common. They are lightweight, which makes them easier to transport to remote areas of Mobile County where heavy trucks can’t go. They are also immune to the corrosive gases that can eat away at concrete. The downside? If they aren’t installed with proper backfill, the pressure of Alabama clay can cause them to collapse or "pop" up during heavy rain.