What is the cost of installing a septic tank?

What is the cost of installing a septic tank? Well unlike a cesspit, the septic tank has some extremely unique features which can affect the cost of maintaining the unit.

In short, a cesspit is a wastewater system which holds the waste until emptied. A septic tank is a wastewater system which not only holds the wastewater but also treats and discharges some of its contents into the environment around it (through a soakaway). This is similar to a Sewer Treatment Plant system.

If you are currently researching the costs of installing one into your home, then there are a few things to consider.


It is very important you have the correct information and permissions in place before beginning your project.

A septic tank can be quite a large size with its tank and soak away to consider. With this in mind, you will need to make sure your ground is suitable for a soakaway and you have the correct planning permission on your land in order to excavate without any trouble.

Even if you would like to install an above ground tank, planning permission will be required.

The size of the tank.

The size of your septic tank will inevitably affect the cost.

The larger the number of people living within the property, the larger the tank will need to be. It is common to think that a larger property will require a larger tank, but if it can only hold a small number of individuals, then the amount of waste created will be less.

A small-sized septic tank can cost upwards of £750, whereas a larger system can cost £1000 – £2000 and beyond.


Location can be everything when researching which system would be the most beneficial. Smaller above-ground systems can be extremely cost-effective, but they can be somewhat of an eyesore.

However, in some circumstances, you may have no other choice but to install a below-ground system.

Consult with an adviser when researching for planning permission before making any financial decisions.

Labour and materials.

Like most things, the materials your system is made from will unsurprisingly affect the cost of the unit. You would potentially assume that all tanks are one and the same, but this is a misconception. Our advice would be not to cut corners and invest in a unit that will give you longevity. The Septic Tank will give you a return on investment over time so make a wise choice.

There are various different trades which offer an installation service, but it is recommended that you discuss an installation with your local waste management company. They will have the best knowledge on what to avoid and the best course of action.


So in an a nutshell, the answer to “What is the cost of installing a septic tank?” is:

Overall, your investment levels will vary depending on the choices made, but on average, the whole project should cost between £3000 – £6000 for supply and installation of a Septic Tank depending on size and ground conditions.

If you wish to learn more about our installation services, please feel free to contact us at any time at 01646 629089 or click here to fill out one of our instant quotation forms. Read our Top Tips for Septic Tank Maintenance here.

Drainage and wet waste specialists

Room F1, Captain Superintendents Building, Admiralty Way, The Dockyard, Pembroke Dock SA72 6TD.
01646 629089