With there set to be an update of the septic tank regulations in the UK in 2020, now is a great time to gain an insight of the costs associated with a domestic sewage treatment plant installation, one of the main alternatives to a septic tank.

One of the main advantages often mentioned about the domestic sewage treatment plant is the speed and the ease of installation. In fact, it can take as little as one or two days of work to have a domestic sewage treatment plant fully installed and functioning. However, what are the costs involved in this installation process?

The Cost of a Domestic Sewage Treatment Plant Installation

Several factors must be considered when implementing a wastewater treatment system:

  • Deciding which system to choose
  • The purchase of the system
  • The installation
  • The servicing and maintenance

The Wastewater Treatment System

domestic-sewage-treatment-plant-installation-costsThe cost of the project is divided into two parts: the analysing of the various wastewater treatment systems and the maintenance of the wastewater treatment system.

The analysis of different systems is an optional cost; it is not obligatory for you to take into account as it is not a mandatory step.

This is a matter of hiring a professional to determine what is the best device for you. However, in this report we’re only talking about domestic sewage treatment plants.

The servicing and maintenance of the wastewater treatment system, on the other hand, is a mandatory cost.

Purchasing of a Domestic Sewage Treatment Plant

In this case, what system you wish to purchase isn’t an issue as we assume you are looking to purchase a domestic sewage treatment plant.

As for how much you will have to pay, it all depends on the size of the plant. For a 6-person model, it will cost between £4500 and £7000, depending on the brand and the exact model. After this, the price goes up with the amount of people the plant was designed for.


Installation costs are trickier to calculate, as it really depends on your site and if the conditions are suitable for an easy installation. If the land requires more earthworks, the price can rise very quickly.

In contrast, if you install the domestic sewage treatment plant near your home and on a flat surface, the cost will be reasonable.


Once installed, the installer should ensure that the treatment system complies with the British Environmental Agency’s general binding rules and regulations.

As mentioned above, in the following years the property owner must continue to have the domestic sewage treatment plant serviced and maintained in accordance with the manufacture’s guidelines. Failure to do this could ultimately result in hefty fines for the property owner.


In most cases the installation of a domestic sewage treatment plant is probably cheaper than the installation of a septic tank, as the septic tank would also have to include a draining field. Domestic sewage treatment plants and septic tanks roughly use up the same amount of ground. However, you must not forget that with the inclusion of a draining field (which is about to become mandatory with the 2020 septic tank regulations update), septic tanks require a lot more space to function.

Although domestic sewage treatment plants may seem expensive to purchase, the overall cost of the operation must be taken into account rather than just simply the cost of the device.