How Much Does It Cost to Get an Underground Tank?

Installing an underground tank is a practical solution for various needs, such as water storage, septic systems, and fuel storage. Understanding the costs involved is crucial for effective planning and budgeting. 

In this blog, we will explain the different factors that influence the overall cost of installing an underground tank. We’ll explore the types of tanks available, their sizes, materials, and the installation process, providing you with a clear picture of what to expect.

Whether you’re considering a small water storage tank or a large fuel tank, this guide will help you make informed decisions and find cost-effective solutions for your specific requirements.

What is the Cost of Installing an Underground Tank?

cost of installing an underground tank
How Much Does It Cost to Get an Underground Tank? 4

The cost of installing an underground tank varies based on several factors, including the type of tank, size, material, location, and additional installation requirements. On average, the cost ranges from €2,500 to €10,000. Here’s a more detailed breakdown:

Type of Tank

Septic Tanks: The cost of septic tanks typically ranges from €1,500 to €2,000 for the tank itself. The additional cost for the percolation area and groundworks can range from €4,500 to €8,000​​.

Water Storage Tanks: The price for water storage tanks varies with capacity and material. For instance, a 3,000-litre rainwater harvesting system starts at around €2,010 ex VAT, while a 10,000-litre tank can cost about €5,595 ex VAT​​​​.

Fuel Tanks: Installing an underground oil tank can be quite expensive, with costs around €10,000. This includes the tank, excavation, and installation costs​​.

Summary of Costs

  • Small Water Tanks (3,000 litres): From €2,010 ex VAT
  • Medium Water Tanks (10,000 litres): From €5,595 ex VAT
  • Large Water Tanks (20,000 litres): From €10,305 ex VAT
  • Septic Tanks: €1,500 – €2,000 (tank only) + €4,500 – €8,000 (installation)
  • Fuel Tanks: Around €10,000

What Factors Affecting the Cost of Installing an Underground Tank?

Several factors can affect the cost of installing an underground tank. Understanding these can help you plan and budget effectively. Here are the key factors:

Type of Tank

The type of tank you choose will significantly impact the cost. Septic tanks, water storage tanks, and fuel tanks have different price ranges. For example, septic tanks cost between €1,500 to €2,000 for the tank itself.

However, the total cost including installation can reach up to €10,000​​. On the other hand, water storage tanks can cost from €2,010 to €10,305, depending on the size​​​​.

Size and Capacity

The size and capacity of the tank also play a crucial role in determining the cost. Smaller tanks, like a 3,000-litre water tank, start at around €2,010. Larger tanks, such as a 10,000-litre tank, can cost about €5,595. For very large tanks, like a 20,000-litre water tank, the cost can go up to €10,305​​​​. Larger tanks require more excavation work and materials, which increases the overall cost.


The material of the tank affects both the initial cost and the longevity of the tank. Common materials include plastic, fibreglass, and concrete. Plastic tanks are usually the cheapest but may not last as long. Fibreglass tanks are more durable and cost more.

Concrete tanks, though the most expensive, offer the best longevity and structural integrity. For example, a concrete septic tank can itself cost between €1,500 to €2,000, excluding installation costs​​​​.

By considering these factors, you can better understand the overall cost of installing an underground tank. This knowledge helps in making informed decisions and finding the best solution for your needs.

What Are the Steps of Installing an Underground Tank?

The installation of an underground tank involves several key steps. Here are the details:


Excavation is the first major step. It involves digging the area where the tank will be placed. Excavation services are crucial to prepare the site for tank installation. Specialised companies in Ireland offer these services to ensure the site is adequately prepared.

Backfill and Compaction

After the tank is placed, backfill and compaction are necessary. This ensures the tank is secure and stable. These steps involve filling the area around the tank with suitable material and compacting it to prevent any movement. This is a standard procedure that ensures the longevity and safety of the installation.

Plumbing and Electrical Work

Connecting the tank to your home’s systems is crucial. Plumbing and electrical work are needed to ensure the tank functions properly. This involves installing the necessary pipes and electrical connections to integrate the tank with your existing systems. Proper installation ensures that the tank can be used for its intended purpose without issues.

Permits and Inspections

Permits and inspections are required by law. They ensure the installation meets local regulations. Obtaining the necessary permits and having the installation inspected is a critical part of the process. This step ensures that all work complies with local building codes and standards.

Installation Costs of an Underground Tank Can Vary

The cost of installing an underground tank can vary widely based on several factors such as the size of the tank, the type of soil, the complexity of the installation, and local labour rates. Because of this variability, it is difficult to provide an accurate cost estimate without detailed information about the specific project.

For the most accurate pricing, it is best to contact a trusted service provider. They can provide a tailored quote based on the specific requirements of your project and ensure that all aspects of the installation are covered comprehensively.

What Are the Location-Based Cost Variations for Installing Underground Tanks?

The cost of installing an underground tank can vary significantly based on the location. Different areas have unique challenges and requirements that can influence the overall cost. Here’s how location can affect your budget:

Urban vs. Rural Installation Costs

Urban areas can be more expensive for tank installations. This is due to higher labour costs, stricter regulations, and potential difficulties with accessing the site. Excavation in urban areas can be more complex because of the dense infrastructure. Navigating around other utilities and limited space can increase labour and equipment costs.

On the other hand, rural installations might have lower labour costs. However, they can still be costly due to transportation fees and the need for specialised equipment to reach remote locations. Rural areas may also have different soil conditions that require additional preparation. For example, rocky or uneven terrain can increase excavation and installation costs.


Installing an underground tank involves various factors like excavation, backfill, plumbing, and permits. Costs can vary widely based on location, type of tank, and specific site conditions. Urban areas generally have higher costs due to labour and regulations, while rural areas might face additional transportation fees. For accurate pricing and professional assistance, it’s best to consult with experts.


  1. What factors affect the cost of installing an underground tank?

 The cost of installing an underground tank depends on factors like the type of tank, size, material, and location. Additional costs include excavation, backfill, plumbing, electrical work, and permits.

  1. How much does it cost to install a septic tank?

A septic tank itself typically costs between €1,500 to €2,000 for the tank itself. However, the total cost, including the percolation area and groundworks, can range from €4,500 to €8,000.

  1. Is it more expensive to install an underground tank in urban areas? 

Yes, urban installations are generally more expensive due to higher labour costs, stricter regulations, and potential access issues. Excavation can be more complex due to dense infrastructure.

  1. How much does a standard 5,000L rainwater harvesting tank cost?

A 5,000L Platin flat rainwater tank typically costs around €2,080 ex VAT (€2,558.40 inc VAT)​.

  1. Do I need permits to install an underground tank?

Planning permission requirements depend on the tank’s size and location. Generally, smaller tanks for personal use may not require permission, but larger installations or those in specific areas might.

  1. How can I get an accurate quote for an underground tank installation? 

For an accurate quote, contact a trusted service provider who can assess your specific needs and provide a detailed estimate. It’s important to consider all factors, including type of tank, location, and additional installation requirements.

Fill Out The Form Below To Make an Enquiry

  • Resolute Engineering Group Ltd.
  • Company No: 671068
  • Working Time Mon - Fri: 09:00 to 17:00