Septic Tank Life Expectancy (Based On Material Type)

One of the most common questions I get regarding septic tanks is how long you can expect them to last. The answer to this varies depending on the material and level of maintenance the tank has seen since it was installed. There are some set standard estimations for septic tank lifespans that you should be aware of.

A septic tank can last anywhere between 20 to 40 years, depending on the material and level of maintenance the tank has seen. Steel septic tanks have the shortest lifespan, maxing out at around 20 years. Plastic septic tanks last considerably longer, with a maximum lifespan of up to 30 years. Finally, concrete septic tanks last the longest, with a maximum lifespan of up to 40 years.

There are many factors that will influence the exact lifespan of your septic tank. These factors will be discussed in detail in the sections below.

Types Of Septic Tanks


Plastic septic tanks are a popular choice for many due to their affordability and ease of installation. They are much more affordable than both steel and concrete tanks and incur fewer maintenance and installation costs.

Because of their lightweight design, they can be easily transported and installed. The installation process is generally quicker with plastic septic tanks. Plastic is a popular material for septic tanks due to its natural resistance to water-based corrosion and rust.

Plastic septic tanks are the most hygienic of all of the septic tank types and can be purchased pre-setup and ready to install. On the other hand, they are much less weight resistant and sturdy than concrete and steel types, making them more sensitive to shifts in the soil.

Plastic Septic Tanks
Plastic Septic Tanks

Plastic septic tanks are also more prone to standard cracks and breaks in the shell of the tank due to their less durable material. An issue that is unique to plastic septic tanks is the possibility of floating issues when water levels rise. Plastic septic tanks are not approved for use in all areas.


Steel septic tanks are popular for being lightweight but more durable than plastic types. That being said, they are rarely used over plastic and concrete types due to their low resistance to corrosion and extra expense. They are generally considered short-term tank solutions until a more suitable one can be installed.

Steel Septic Tank
Steel Septic Tank


Concrete septic tanks are a popular choice for added durability but have higher costs to install, maintain, and remove. They have great resistance to environmental conditions and are strong enough to withstand shifts in the soil that would crush a plastic septic tank.

They have one of the longest lifespans of any of the septic tank types, with some lasting up to 40 years if properly maintained. They are approved for use in all areas and will not float in the event of rising water levels.

Concrete Septic Tank
Concrete Septic Tank

They are, however much more prone to water-based corrosion and rust. Because of the amount of water exposure, it is important to routinely inspect concrete septic tanks for damage and rust. They are much harder to install than plastic and steel types due to their extra weight.

How Long Does Septic Tank Last?

There are a variety of different septic tank systems and materials for your home. On average, a septic tank can last anywhere between 20 to 40 years, depending on the material and the level of maintenance over the years. Steel septic tanks have the shortest lifespan, lasting on average only 20 years maximum.

Plastic septic tanks are designed to last longer due to their resistance to corrosion, for a maximum lifespan of 30 years. Finally, concrete septic tanks have the longest lifespan of all, up to 40 years in some instances.

Keep in mind that these life expectancies are for tanks that have been well maintained during their lifetimes. If you do not care for your tank properly during its lifetime, it is likely that you will need to replace your tank much sooner than normal. A table has been included below containing the average lifespans of all three septic tank types.

Septic Tank TypeAverage Lifespan(Years)

Being aware of the different factors that influence your septic tank’s lifespan can help you get the most operation time out of your tank.

Factors That Influence A Septic Tank’s Lifespan

Listed below are several different factors that play a key role in determining the total lifespan of your septic tank.


The location of your septic tank can heavily influence how long it lasts. Placing your septic tank in an area with heavy traffic puts it at risk of being crushed by the pressure or shifts in the soil. You should also consider the proximity to trees and other foliage in the area, as roots could grow and penetrate the tank and pipes.

When this happens, the tank will likely need to be replaced much sooner than normal due to the damage sustained. Even if you are able to repair the damage, if you do not change the location, eventually, the same issue will arise again. This makes choosing the proper location for your septic tank vital for ensuring a long lifespan.


Of course, the material that you choose for your septic tank will play a major role in determining how long it last. Should you choose a steel septic tank, you could find yourself having to replace it two decades sooner than if you chose a concrete type to install.

You should consider all of the factors when choosing a septic tank material, including affordability and durability. Concrete septic tanks are much less prone to damage from shifting soil or roots, while plastic septic tanks can be easily damaged.


How often you get your tank service when issues arise will also play a role in determining its lifespan. If you keep your tank regularly serviced, especially when issues arise, you can guarantee a longer lifespan. Letting issues pile up and go unaddressed can lead to a damaged septic tank.

Servicing is an important part of your septic tank’s lifespan. The more on top of servicing your tank you are, the longer you can expect your tank to last in the long run. It is advised that you have your tank serviced at least every year or whenever you begin to experience issues.  

What Is Going Into It

Another thing that will influence the lifespan of your septic tank is what is going down the pipes and into the tank. While septic tanks are designed to house plumbing from your home, they do not tolerate large amounts of solids very well.

This is especially noticeable if you have large amounts of food particles or solid items draining into the tank from the sink or toilet. The more non-biodegradable objects that enter the tank, the more likely you are to have issues down the line.

Frequency Of Use

How much water you use in your home will also influence the lifespan of your tank. If you have a small septic tank and a large household, the amount of water passing through it could overwhelm it and cause issues.

In some serious cases, too much water passing through in a short amount of time could damage the internal components of your tank, causing them to need to be replaced. Overutilizing your septic tank system will lower its lifespan and cause issues with your plumbing over time.

How Often It Is Emptied And Cleaned

The more you clean and empty your septic tank, the healthier it will be. This will lead to a longer-lasting tank. If you have not been emptying or cleaning your tank properly, there is a good chance that the sludge buildup could cause problems with your tank.

A tank that has not been emptied properly will have a much shorter lifespan than one that has been properly maintained. It is advised that you get your tank fully emptied at least once every few years, depending on how much it is used and the size of the tank.

How It Was Installed

The quality of the installation will also play a key role in influencing the lifespan of your septic tank. If your septic tank has not been installed correctly, it will have a considerably shorter lifespan. Proper installation includes ensuring a good location, proper piping, and placement beneath the soil.

It is also important to know what can and cannot be put into a septic tank. This can help lengthen the lifespan of your tank by avoiding the buildup of foreign bodies in the tank.

What You Can And Can’t Put In A Septic Tank

Your septic tank is only designed for use with liquid, toilet paper, and wastewater from your home. Other items that enter the septic tank system can cause serious issues that could cause a sewage backup in your yard or home.

Because of this, it is important that you pay close attention to the things that you are flushing down the drains and toilets. This is especially important for those who use a garbage disposal with their septic tank system.

A full list of items that are NOT recommended to be introduced to your septic tank has been listed below. Avoiding allowing these items to go down the drains will help ensure a long life for your septic tank. These items include:

Flushing toilet paper in bowl
Flushing toilet paper in bowl
  • Any type of hazardous waste
  • Diapers
  • Cat Litter
  • Paper Towels
  • Feminine Hygiene Products
  • Cigarettes
  • Gasoline
  • The pits or peels of fruits
  • Tough, stringy vegetable scraps like celery or corn husks
  • The skins of onions
  • Eggshells
  • Starches like pasta, rice, and oatmeal
  • Nuts
  • Any type of meat
  • Coffee grounds
  • Soils
  • Fats or oils
  • Any non-food items

Acidic Soil And Groundwater Concerns

The acidity of the soil where your septic tank is located will influence the lifespan of your tank as well. Highly acidic soil can have corrosive effects on your septic tank, which could cause breaches in the tank’s shell.

When this happens, the tank will need to be repaired or replaced. It is important that you test the acidity levels of the soil in any area in which you are considering installing your tank. Your tank’s lifespan will be considerably shorter when exposed to soil with high acidity levels.

Exposure to groundwater can also accelerate the corrosion process and, in some cases, displace your tank entirely if the water levels rise. This is why proper planning and placement of your tank are so important.  

Another important thing to consider is the signs of a failing septic system. This will be covered in the next section.

Signs Of Septic System Failure

The most common signs of septic tank failure are plumbing issues inside your home, sewage backup, and large puddles of foul water around the area of the tank. When a septic tank system fails, untreated sewage and drain water will be transported through your system to places it doesn’t belong.

This can cause sewer backup to pool in your yard or up through your drains, toilets, and sinks. In some cases, the sewage leak could leech into surrounding waterways, contaminating them with harmful bacteria. If this happens, you could possibly face serious criminal charges if you do not address the issue as soon as possible.

This includes well water, ponds, and nearby marine water that may be present. A failed septic tank system will also cause general plumbing issues that can be expensive to resolve. You should regularly empty your septic tank and perform scheduled maintenance to avoid these issues.

Common Septic Problems

Root Damage

Damage from tree roots is one of the most common septic problems that I see people encounter. Because you cannot control directly how the tree roots grow, it can be difficult to plan for this problem. When a tree root grows into the tank or the surrounding pipes, it will be major damage to the entire system. This is why placing your septic tank away from trees is vital to the longevity of the tank.

Root Damage on Pipe

Flushing Non-Biodegradable Items

Flushing non-biodegradable items is another common cause of septic tank problems. A septic tank is only designed to process toilet paper and wastewater from your home. Any other foreign materials introduced in the tank will build up in the tank and potentially cause clogging or sewage backup.

Using Harmful Products

Many products like bleach, detergents, and other solvents can inadvertently damage the bacteria and enzyme populations in your septic tank. These bacteria and enzymes are responsible for breaking down materials in the tank naturally to avoid sludge buildup. Damaging these bacteria with harmful products will lower the overall efficiency of your tank.

Physical Damage

Of course, physical damage from vehicles or soil shifting is another common issue that can arise. Any time a vehicle passes over the area your septic tank is located, there is a chance the added pressure will damage the tank buried beneath. You should place the tank in an area of low traffic to avoid this.

Poor Design And Installation

If you do not ensure proper planning and installation of your septic system, you will likely experience unforeseen issues. Being aware of the soil type, groundwater levels, and tree locations will help you avoid problems in the future. Ignoring these factors guarantees problems that could potentially shorten the lifespan of your tank.

Poor Or No Maintenance

One of the most common problems I see people having with their septic tank system is a poor maintenance routine. Your septic tank depends on routine maintenance to function properly. A septic tank system that has not been properly cared for will have a much higher chance of failing.

Proper maintenance includes regular inspections and emptying of the tank. This will ensure your tank can reach the maximum lifespan.

Hydraulic Overload

Hydraulic overload refers to when your septic tank has processed more water at once than it can handle. When this happens, wastewater will be introduced to areas where it does not belong, potentially causing sewage backup in your home or yard.

You should moderate how much water is being passed at one time to avoid this issue. Regular inspection is necessary to check for all of the issues listed above. The process for inspecting your septic system will be detailed below.

How To Perform A Septic Inspection

You can perform the standard septic inspection by being aware of the different signs of a failing septic system. These include:

  • Drains that empty slower than they should.
  • Sewage backing up through the sinks, drains, and toilets in your home.
  • Foul-smelling pools of standing water in your yard.
  • Noticeable drainage and plumbing issues during the rain.
  • A tank that needs to be pumped more than once a year.
  • Greener, healthier grass in areas around the tank.

Being aware of all of these signs of a failing septic system can help you catch issues early so that you can address them as soon as possible. Trace dye tablets can also be used to perform a more detailed inspection.

Using Trace Dye Tablets To Perform A Septic Inspection

If you have noticed some of the signs of a failing septic tank system, you should use trace dye tablets to know for sure that you have an issue. Trace dye tablets can be flushed down the toilet and help reveal the source of your issue by showing the dye pooled in the water near the drain field of the tank.

How Often Should My Septic Tank Be Pumped

It is recommended that you have your septic tank emptied at least once every three to five years. The exact amount of time in between emptying will depend largely on how much it is used and how well-maintained it is.

For example, a single person in a household could go up to ten years without having to empty their septic tank, while a family could wind up needing to empty theirs every year. It is advised that you make a note of the interval between emptying so you can create a schedule going forward.

If you find that your tank has reached the end of its life, you may be wondering how long it takes to be replaced. This will be covered in the section below.

How Long Does It Take To Replace A Septic Tank?

Replacing a septic tank with a new one can be a lengthy process, sometimes taking up to 3 to 4 months to complete. This is because the old one will need to be removed, and the area made fit again for installation before it can proceed.

Because of the length of this process, it is important that you keep your septic tank as healthy as possible to put off the inevitable replacement for as long as possible. There is also the cost associated with replacing your septic tank to consider.

How Much Does It Cost To Replace Septic Tank?

It can cost anywhere between $6000 to $20,000 to remove and replace your septic tank. The actual cost will depend on the type of tank you have chosen as a replacement and the labor cost associated with removing and replacing the tank.


If you take care of your septic tank, it can last between 20 and 40 years, depending on the type of tank you have installed. Tanks that have not been properly cared for will likely have lifespans considerably shorter.

If you are looking for a tank with the maximum lifespan, a concrete septic tank is best suited for you. Keep in mind that other factors can influence the lifespan of your tank including location, installation quality, and environmental factors.

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