Plastic septic tanks weigh much less than concrete septic tanks and are 100 percent corrosion-resistant. Concrete septic tanks are strong and durable. A well-maintained concrete septic tank can last for generations.
A concrete septic tank will cost more to install and maintain than a plastic septic tank. Because plastic septic tanks are lightweight, they are more prone to damage during installation.
Some states do not allow plastic septic tanks. All 50 states allow concrete septic tanks.
Concrete septic tanks are more prone to cracking and leaking than plastic septic tanks, particularly in extreme cold. Improperly installing and poorly maintaining plastic septic tanks can increase the likelihood of cracking and leaking.
Because they are so lightweight, plastic septic tanks can float to the surface of the ground if they are improperly installed. Concrete septic tanks will never float up to the surface because they are so heavy.