How Long Will My Septic System Last?

Septic tanks are one of the essential features for homes not connected to the municipal or city sewer system. A goodExternal link opens in new tab or window septic system keeps your property clean for years by trapping and filtering your sewage and domestic wastewater. The durability of the system may hinge on the type of material used to construct the septic tank.

Fortunately, you can choose from a wide variety ofExternal link opens in new tab or window septic tank materials such as concrete, plastics, steel, and fiberglass. Here is a more detailed look into the different types of materials and their unique benefits.

Concrete Septic Tank

Precast concrete tanks are the preferred option for most households, especially in rural settings. Concrete is durable, corrosion-resistant, and watertight, making it an excellent material for storing and treating domestic wastewater.

Concrete septic tanks can either be single-structure tanks or all-in-one systems. Single-structure septics have each chamber precast separately, while all-in-one systems have all chambers molded in one large tank. The heavy concrete blocks may require heavy machinery such as cranes for installation.


  • Concrete is rust- and corrosion-proof, making the septic tank last longer

  • The tanks are heavy enough to withstand buoyancy forces

  • Concrete tanks are typically traffic-rated

  • The septic system is easily customizable to your needs


  • The need for specialized equipment can make the installation expensive

  • It can be hard to repair when damaged

Plastic Septic Tanks

Plastic septic systems are constructed from polyethylene or polypropylene molds. The tanks are lightweight and easy to install. However, the lower density may cause issues in high-water table areas. With a specific gravity of 0.98, the tanks can float out of the ground if the water level is high enough.

Plastic septic tanks are corrosion and rust-resistant. The ribbed or corrugated design may increase the tank’s structural performance.


  • Plastic septic tanks are easier to install

  • The tank is chemical- and rust-resistant

  • Plastic tanks are more economical than concrete systems


  • The plastic tank may float in areas with high water tables

  •  The capacities are often smaller

  • The plastic septic tank may require stringent installation requirements to maintain structural integrity

Fiberglass Septic Tanks

Fiberglass systems are similar to plastic septic tanks. The tanks useExternal link opens in new tab or window reinforced glass fibers, making them stronger than the polyethylene plastic types. Fiberglass is lightweight, corrosion-resistant, and easy to install.

The lightweight nature of the fiberglass septic tanks may necessitate proper anchoring to the ground to prevent shifting in soils with high water tables.


  • Fiberglass is lightweight and easier to install, especially in limited spaces

  • The glass fibers are resistant to rust and chemical corrosion

  • The tanks are available in larger capacities


  • The lightweight nature can cause the tank to float above the ground

  • Strict installation requirements to maintain the tank’s structural integrity

Which Is the Best Material For Your Septic Tank?

The suitable material for your septic tank project may depend on your specific preferences. Concrete tanks may provide the best resistance to buoyancy due to their weight. Homeowners with limited space may consider fiberglass or plastic installations as they do not require any specialized equipment.

You may need to consult a professional septic tank installation company. Licensed contractors can carry out reliable soil and water tests to guide you in picking the right material for your septic system.