You don’t like to talk about it but there’s a lot riding on your home’s septic tank. It’s used to store and process all the waste water from your home. If the septic tank breaks or malfunctions, it needs to be repaired or replaced immediately.

And if you don’t take any action? It could damage the plumbing system or even leak into your house structure. You could be looking at thousands of dollars in damages.

Septic tanks don’t have a long functional life, which is why you should replace them before any problem arises.

When getting a septic tank, you’ll need to choose between two types: concrete and plastic septic tanks.

In this well-researched post I’ll help you make the right call.

Ready? Let’s dive in (not into the septic tank though!)…

Without further ado, let’s move on to the comparison between the two types of tanks.

Concrete vs Plastic Septic Tanks

Sometimes the best way to compare two options is to simply go through their pros and cons. Afterwards, I’ll dive in to more tips on choosing between the two.

Concrete Septic Tank Pros

A major benefit of concrete septic tanks is that they’re much more durable and heavy. This makes them long-lasting and suitable for all types of weather conditions and climates.

Since they’re heavy, they settle in the soil well enough, not moving around or floating. This also helps them withstand external pressure due to being buried in the soil.

concrete septic tank
Concrete Septic Tanks can last up to 40 years with very little maintenance

With proper maintenance, a concrete septic tank can last up to 40 years. And it also requires very little maintenance.

It doesn’t get damaged or affected by soil conditions or tree roots.

Last but not the least, these tanks are also certified safe for use in the US.

Concrete Sepic Tank Cons

While there are a lot of benefits of going with a concrete one, there are also some downsides.

First off, they’re quite expensive to buy and install, mainly due to their weight. Moreover, the weight also makes it difficult to transport them to your home after you buy it.

Although they’re much more durable, when these tanks get damaged, they can be quite difficult to repair or replace.

These septic tanks are also prone to corrosion, which then renders them unsuitable for use.

Let’s look at why you should, or shouldn’t, buy and install a plastic septic tank for your home.

Plastic Septic Tank Pros

One of the major benefits of plastic septic tanks is that they’re much cheaper than ones made from concrete or other materials.

This makes them a cost-effective investment, especially if they need to be replaced every few years.

Black plastic septic tank
Plastic Septic Tanks are cheaper and easier to transfer and install.

Since plastic is also lightweight, these septic tanks are easier to transport and install. This further keeps installation costs down.

You can also install them in several locations, a feature that wouldn’t get with concrete ones.

Plastic septic tanks are also quite durable and flexible, which is why they don’t crack very easily.

They’re also more hygienic than the latter, and are corrosion-resistant, which offers them a long life.

Plastic Septik Tank Cons

One major downside of installing a plastic septic tank in your home is that it can get crushed by the weight of the soil. Or from the pressure of people and vehicles passing above it.

It can also get damaged due to the soil conditions or tremors in the ground. This is why these septic tanks don’t have a much longer life as concrete tanks do.

They also require more maintenance, which is why it’s better to replace them whenever a problem occurs.

Another disadvantage of choosing these types of septic tanks is that they may float if the water level is too high. This can damage the plumbing system.

Finally, they’re also not approved for use in most states, so you’ll have to check for this before you buy a plastic septic tank.

How to Choose Between these Two Septic Tanks?

So, how do you decide between concrete vs plastic spetic tanks?

I’ll make it simple for you by listing down the key factors you should consider.


Cost is one of the major factors when you’re choosing between the two tank types.

A concrete septic tank costs much more than a plastic one. And its installation is also more costly.

However, the concrete tank may last for a good 20-30 years, justifying its price.

On the other hand, a plastic one may not last for more than 3-5 years, and you’ll have to replace it every few years. So see which one suits you more.


If you’re replacing your old septic tank, make sure to know its dimensions and get one that’s of the same size.

This will help you install it much faster and without any hassle.

However, if you’re working on a new construction, make sure to have your contractor measure and advise you on which size you should go for.

Ideally, the size of a septic tank is determined by the amount of water consumed by a household per day.

If you consume less than 500 gallons of water, then a 900-gallon tank is enough. This is considering that it’ll have to process wastewater, which is heavier than normal water.


It may not mean much, but the design of the septic tank is also crucial.

For instance, if your septic tank will be buried within gravel or coarse soil, you can use a pressure-type septic system.

If there’s rich soil, you can make do with a gravity system. Make sure you have an idea of the type of soil you’re dealing with.


No matter how big or small your septic tank is, it may have one or two different types of pumps.

The most common of them is the turbine pump, which lasts longer than the others.

You can also make use of the centrifugal pump, which isn’t as durable but is more cost-effective.


When it comes to durability, concrete septic tanks can withstand much more damage or breakage than plastic septic tanks.

Although the latter are flexible, they can get damaged much easier than the concrete ones. They also sit in place quite well because of their weight.

How Do I Know My Septic Tank Needs Replacement?

If there’s a pungent or awful swell around your house, that’s a sign you may need to replace your septic tank.

If you know where your septic tank is, and you notice a strange or strong smell around it, it can also be a sign of septic malfunction.

Other signs include:

  • You notice wastewater pumping back into the household drains.
  • You notice bright green and spongy grass on the drain field, without any rain or moisture.
  • There’s water buildup around your septic tank or inside your basement.

If you find any of these signs, it’s high time for you to replace the septic tank.

How Do Septic Tanks Work?

Septic tanks are needed in homes that don’t have access to the municipal water system. When such homes are constructed, the sewage pipes are connected to the septic tank, which is underground.

All the wastewater from the house is flushed out to it. It holds the water for a long time, allowing the solids to settle on the bottom and the greasy residue to float at the top.

black septic tank

After some time, the liquid wastewater is drained into the drainfield, which is a dug out area in unsaturated soil. The pretreated wastewater is discharged through a pipe onto a porous surface.

The soil traps the waste and lets the water pass through, which is ultimately mixed with groundwater.


So you can see that choosing between a concrete and plastic septic tank means understanding which factors are more relevant to you.

At the end of the day, a well-maintained, properly functioning septic tank will do its job well. You just need to find out which one is more suitable for you.

And I hope this article helped you recognize the difference between concrete and plastic septic tanks. And which one might be the better choice for your home.

If you liked this post, do check out other similar articles on our site.

Thank you for reading, and have a great day!