When Replacing Your Home's Septic Tank, Should You Stick With Concrete Or Opt For Plastic?

If it's time to replace your aging septic tank, you may be wondering which material to choose. Concrete has typically been the material of choice due to its durability, and it continues to see use in new construction. However, high-density polyethylene plastic tanks are becoming increasingly popular due to their lower cost. While not as durable as concrete, they're much lighter and easier to install. To find out which would suit your home best, read on to learn about the most important differences between concrete septic tanks and plastic ones.

Plastic Tanks Are Less Expensive to Buy and Install

When you're comparing plastic septic tanks to concrete ones, the immediate difference that you'll notice is that plastic tanks are much cheaper. You can even purchase them in home improvement stores if you're willing to install a new tank as a DIY project.

Concrete tanks can either be poured or installed pre-cast. Pouring concrete into the ground in order to create a septic tank is generally reserved for new construction homes since you won't be able to use your home's plumbing until the concrete has cured. When replacing your tank, it's better to opt for a pre-cast concrete septic tank. These cure at the factory, so they're ready to be used immediately. However, they're extremely heavy—you'll likely need a crane in order to install one, and this requirement drives up installation costs. Due to their lighter weight, plastic tanks are much easier and less expensive to install.

Concrete Tanks Have Superior Durability

While you'll pay extra for a concrete septic tank, you'll benefit from its increased durability. You should never drive vehicles over your septic tank, regardless of what material it's made from, but concrete will hold up much better if a car or truck drives over it. Any heavy vehicles that drive over a plastic septic tank will very likely cause it to collapse or break in two, which means you'll need to immediately replace it. If a vehicle drives over a concrete tank, the tank is unlikely to suffer damage.

Plastic Tanks Are Prone to Floating

The biggest downside of using a plastic septic tank is that its low weight makes it buoyant. When the local water table is high, a plastic tank can begin to float upwards. It's unlikely that the tank will breach the surface, but even small movements can cause the pipes leading to the tank to break. You'll need to have them repaired in order to use your septic system. With concrete, you never have to worry about the local water table—the tanks are so heavy that they won't float upwards.

You can minimize the risk of your plastic tank floating by only pumping it during the dry season. Plastic tanks are more likely to float when they're empty since that's when they weigh the least. Pumping out your plastic tank during the rainy season, when the water table is high, can lead to it shifting upwards within the soil, which will damage your septic system.

Which is the right choice for your new septic tank? In general, plastic tanks will be the best type for most homeowners. As long as you're careful to only pump it during the dry season and to never drive over it, it'll last for a considerable amount of time. However, concrete is a better choice when you'd prefer your tank to not require as much care. You'll pay more for a concrete septic tank, but concrete's increased durability means that you'll experience fewer maintenance hassles.

To learn more, contact a septic tank company.


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