Fiberglass Septic Tanks Vs Concrete

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If you are in the market for a new septic tank, you may be wondering whether to choose a fiberglass or concrete model. Both types of septic tanks have their advantages and disadvantages, and your choice will depend on your specific needs and preferences. In this article, we will compare Fiberglass Septic Tanks vs Concrete Tanks.

Fiberglass Septic Tanks

Fiberglass septic tanks are made of reinforced plastic and have gained popularity over the years due to their durability, longevity, and ease of installation. Here are some pros and cons of fiberglass septic tanks.


1. Lightweight And Easy To Install

One of the most significant advantages of fiberglass septic tanks is their lightweight and easy-to-install nature. Compared to a comparable concrete tank, a fiberglass septic tank can be up to 30 times lighter.

2. Resistant To Corrosion And Rust

Fiberglass septic tanks are also highly resistant to corrosion and rust, making them an excellent option for homeowners who want a low-maintenance and long-lasting septic tank. Unlike concrete tanks, fiberglass tanks do not require any waterproofing coating, and they are insensitive to stray electrical currents. They also do not require seal replacement or overlay throughout their life, providing total peace of mind for years to come.

3. Durable And Long-Lasting

Fiberglass septic tanks are known for their durability and long-lasting performance. They are impermeable and have a monohull design. They are also resistant to weather conditions, such as freezing temperatures, and do not require any special monitoring or maintenance.

4. More Scalable Than Concrete

On the other hand, fiberglass septic tanks are more scalable than concrete tanks, making them an ideal choice for larger households or commercial properties. They are easier to connect complementary tanks, and their modular design allows for flexible and customizable installation options.

5. Cost-Effective

Fiberglass septic tanks are a practical and affordable choice for anyone looking for a reliable and efficient septic system.


1. Prone to Floating

One of the drawbacks of fiberglass septic tanks is their tendency to float and pop out of the ground when groundwater levels rise. This is because fiberglass is a lighter material than concrete and is not as dense. When a fiberglass tank is not properly anchored, it can float to the surface and potentially cause damage to the system. To prevent this from happening, it is important to ensure that the tank is properly installed and anchored to the ground. This can be achieved by using heavy-duty straps or chains to secure the tank in place.

2. Not Suitable for High-Traffic Areas

Another potential drawback of fiberglass septic tanks is that they are not suitable for high-traffic areas. They can be easily damaged when heavy equipment or vehicles drive over them, which can lead to costly repairs or replacements.

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Concrete Septic Tanks

Fiberglass Septic Tanks vs Concrete

Concrete septic tanks have been used for years and are still popular in many areas. Here are some pros and cons of concrete septic tanks.


1. Resist Buoyant Forces

Concrete septic tanks are resistant to buoyant forces, which makes them a reliable choice for wastewater management. When a septic tank is pumped empty, it can create a void space beneath the tank, which can cause the tank to float or collapse if it’s not properly designed or constructed. However, concrete is a heavy and dense material that is not easily affected by these forces.

Concrete tanks are designed with the appropriate weight and dimensions to resist buoyant forces and prevent any damage or disruption to the tank or surrounding area. This ensures that the tank remains stable and functional even after being pumped empty. Homeowners and businesses can have peace of mind knowing that their concrete septic tank will remain in place and continue to perform effectively, even under challenging conditions.

2. Long-Lasting

Concrete septic tanks are well-known for their longevity, often lasting for several decades when properly maintained. This makes them a popular choice among homeowners and businesses looking for a long-term solution for wastewater management. Concrete is a highly durable material that can withstand harsh environmental conditions and is resistant to damage from insects and rodents.

Additionally, a concrete septic tank requires minimal maintenance beyond periodic inspections and pumping. While concrete tanks may have a higher initial cost compared to other materials, their long lifespan can make them a worthwhile investment in the long run. Proper installation and regular maintenance, including regular cleaning and pumping, can help extend the lifespan of a concrete septic tank even further. Overall, for those looking for a reliable and long-lasting septic system, a concrete tank is a solid choice.


1. Prone To Corrosion

Concrete septic tanks are a popular choice for wastewater management due to their durability and long lifespan. However, they are not immune to corrosion, which can cause significant problems over time. One of the main causes of corrosion in concrete tanks is the presence of sulphuric acid. This acid is a by-product of the anaerobic digestion process that occurs within the tank, where anaerobic bacteria break down organic matter into methane gas and other compounds. As the sulphuric acid accumulates, it can corrode the concrete, causing leaks and structural damage.

In addition to the acid produced within the tank, the soil in which the tank is buried can also contribute to corrosion. Acidic soil can slowly erode the concrete, compromising the tank’s structural integrity.

Another factor that can contribute to corrosion in concrete septic tanks is the use of harsh chemicals. Chemicals like bleach, drain cleaners, and other cleaning products can cause the concrete to deteriorate over time, leading to leaks and other issues.

To prevent corrosion in concrete septic tanks, it’s essential to regularly inspect the tank for signs of damage or wear. Maintaining the proper pH balance in the tank can also help minimize the effects of sulphuric acid. Additionally, it’s important to avoid using harsh chemicals that can damage the tank’s structure.

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2. Difficult To Install

Concrete tanks are heavy and difficult to install, requiring heavy equipment and trained personnel.

3. Expensive

Concrete septic tanks are known for their durability and long lifespan, but they come with a hefty price tag. Compared to other materials like plastic or fiberglass, concrete is much more expensive to produce and transport, which translates to a higher cost for consumers. Additionally, the installation process for concrete tanks can be more complex and time-consuming, which also adds to the overall cost.

While the initial investment in a concrete septic tank may be higher, some homeowners may see it as a worthwhile expense due to its durability and longevity. However, for those on a tight budget, there are more affordable options available that still provide reliable wastewater management. Ultimately, the cost of a septic tank will depend on factors like material, size, location, and installation requirements.

Fiberglass Septic Tanks vs Concrete: FAQs

Here is a list of Frequently Asked Questions about Fiberglass Septic Tanks vs Concrete:

Fiberglass Septic Tank Cost

The cost of fiberglass septic tanks can vary depending on several factors such as size, installation requirements, and location. On average, a standard 1000 gallon fiberglass septic tank can cost anywhere from $1200 to $2000. However, larger tanks or those with more complex installation requirements may cost more.

How long will a fiberglass septic tank last?

Fiberglass septic tanks are known for their durability and can last for a long time when properly installed and maintained. On average, a well-maintained fiberglass septic tank can last for 20 to 30 years, or even longer in some cases.

Fiberglass is a strong and resilient material that can withstand harsh environmental conditions, such as extreme temperatures, corrosive soils, and high groundwater levels. Additionally, fiberglass tanks are impermeable, meaning they are less susceptible to cracks and leaks that can occur in concrete tanks over time.

What kind of septic tank lasts the longest?

When it comes to the longevity of septic tanks, concrete septic tanks are known to be a reliable option that can last up to 40 years or more with proper care and maintenance. Concrete tanks are strong and durable, able to resist buoyant forces and external pressures that can affect the stability of the tank.

However, concrete tanks are also prone to corrosion and rust over time, which can lead to leaks and structural damage if not properly maintained. Regular pumping, inspection, and maintenance are important to ensure the longevity of a concrete septic tank.

While fiberglass septic tanks are also known for their durability and longevity, concrete tanks have been a popular choice for decades and continue to be a reliable option for homeowners and businesses alike. With proper care and maintenance, a well-built concrete septic tank can provide reliable service for up to 40 years or more.

Fiberglass Septic Tanks vs Concrete: Regulations

When it comes to septic tanks, there are various regulations that must be followed to ensure compliance with local and national laws. Both fiberglass and concrete septic tanks must meet these regulations to be considered safe and legal for use. These regulations can include minimum distance requirements from property lines and water sources, tank size and capacity, and installation guidelines.

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It’s important to consult with local authorities and professionals to ensure that you choose a septic tank that meets all relevant regulations. While there may be some variations in regulations between fiberglass and concrete septic tanks, both must meet the same basic requirements to be considered safe and legal for use.

Fiberglass Septic Tanks vs Concrete: Installation

Installation is a crucial aspect to consider when choosing between fiberglass and concrete septic tanks. Concrete tanks are heavy and difficult to install, requiring heavy equipment and trained personnel. Fiberglass tanks, on the other hand, are lightweight and easy to install, typically requiring only a small crew and minimal equipment. This can result in significant cost savings for installation and maintenance.

Additionally, fiberglass tanks are more scalable than concrete, making it easier to connect complementary tanks. However, fiberglass tanks are not suitable for high-traffic areas and can be damaged if heavy equipment is driven over them. Overall, the installation process for fiberglass and concrete tanks differs significantly, and it’s important to consider the specific requirements of your property before making a decision.

Fiberglass Septic Tanks vs Concrete: Weather

Weather is an important factor to consider when choosing between fiberglass and concrete septic tanks. Concrete tanks can expand and contract due to changes in weather, such as extreme temperature fluctuations between summer and winter. This can cause cracks in the tank, leading to leaks and structural damage over time. Fiberglass tanks, on the other hand, are not affected by weather in the same way.

Due to their monohull and impermeable nature, they require no waterproofing coating, and no special monitoring is required. Additionally, they are insensitive to stray electrical currents, and no seal replacement or overlay is necessary throughout the life of the tank. Overall, weather can have a significant impact on the durability and longevity of concrete and fiberglass tanks, and it’s important to consider this when making a decision.

What happens if a septic tank partition fails or is absent?

Without a functioning partition or if it fails, solids may pass into the drain field, potentially causing clogs and soil contamination. Regular maintenance and inspections can help prevent such issues and prolong the life of your septic system.

Fiberglass Septic Tanks vs Concrete: Final Thoughts

Ultimately, the choice between fiberglass and concrete septic tanks will depend on a variety of factors, including the specific needs of the property, soil conditions, local regulations, and budget considerations. It is important to consult with a professional septic system installer to determine which type of tank is best for your individual situation and to ensure proper installation and maintenance for optimal performance and longevity.