Skip to content

Septic Tank Installations from expert installers.  Get in touch for a Free Quotation.

We offer a FREE inspection or quotation for any Septic Tank Problem or Installation query in the UK.  We are happy to help. Get in touch with us on 0800 3101092 or via our contact form


Septic Tank Installation UK

 Get in contact with us on 0800 3101092  or via our Contact Page

A guide to the Septic Tank installation process

Here is an introduction to our Septic Tank Installation process. Below are the key steps in how we build and design a brand new system. Here at Homeseptic we would rather repair and deal with your Septic Tank problems than carry out a costly new install. However, Septic Tanks and more frequently their Soakaways fail, it is inevitable in their design. Rest assured we will not recommend a new install unless needed. We operate throughout the South of the UK. All of our Engineers and contractors are fully trained and insured. We provide solutions for all ground types, including clay and our professional work is fully guaranteed. In addition, we offer competitive maintenance and emptying package to ensure the maximum longevity of the installed system.

Just before you read on, please read our guide Should I install a septic tank or a sewage treatment plant?

  • Design and Problem Solving

The first step is normally a free site visit. We will assume in this example that the visit has been arranged to quote for an Installation. To be clear we are also happy to arrange a free visit in response to a Septic Tank problem. We will firstly asses whether it is likely that you will gain the necessary permissions to install a septic tank. In today’s regulatory environment it is unlikely; you will likely have to install a Sewerage treatment plant.

We will then plan access and give you the options for the possible site of the tank and Soakaway. The quote and solution will depend on where you would like the site. Once you have chosen the site we will carry out a full survey. This will include a percolation test to assess the size of the new Soakaway or Drainage Field. A percolation test is critical to ensure the Soakaway or Drainage Field has the capacity to store and process the level of waste you will be emitting. Direct discharge is also an option but no longer for Septic Tanks. Cost increases the bigger the Soakaway and the further from your property the associated pipework will need to travel.

Based on a simple calculation we will let you know the size of the tank you will need. Please, see our blog post, What Septic tank size for my house?  We will then walk you through the different tank options available. We will give you an assessment of the different tank’s strengths and weaknesses as well as cost.  Please see our guide choosing the right Septic Tank for more information.

Each site has its own complications. Rest assured we will have a solution and will take you clearly through all of the options.

  • Installation

Once the design and survey stage is completed and all of the details are arranged we move onto the installation. An Installation of a new Septic Tank and Soakaway generally takes a week to complete. Our team will arrive on site Monday morning and will look to complete it on Friday. Our lead drainage engineer will then take you through the install and how to operate the system. Once you have signed off on the job we will leave. The aim is that the next time you will need to see us is for the yearly service and empty. We will, of course, be available to support any queries you have.

What are the regulations around Septic Tank Installations?

Please see our regulation page for more detail. The key elements are the following pieces of legislation:

Small sewage discharges in England: general binding rules

Building regulations approval 

Septic tanks and treatment plants: permits and general binding rules

There are also local specific rules for instance in the New Forest we have the following advice available. Rest assured if you use our services we will have all of this covered for any job in the UK.

How much does a Septic Tank Installation in the UK cost?

There is not a one size fits all answer to this question as you would expect. The main factors that impact the cost of the job are the size of the Drainage Field or Soakaway needed. The size and type of tank you wish to be installed. The length of the trenched piping required to meet building regulations and your own design. Ease of access to your property, if we cannot get the required size of the plant to the desired site then the installation will take longer. Generally, in the UK the average cost of a septic tank installation and associated Soakaway is between £8,000 and £20,000.   

Do we undertake Domestic Septic Tank installations?

Yes, we do, we undertake both commercial and domestic installation work.

What types of Septic Tanks are there in the market?

Please see our section on choosing a Septic Tank. There are several large brands in the market. Top branded tanks are obviously costed at a premium. However, they can be more reliable and their warranties are generally longer and with an established company more reliable.  The key brands are Kingspan Klargester visit here. Graf visit here. Tricel, visit here and the Premier  Tech Condor series, visit here

We install the major brands and more. It is very much horses for courses and of course cost is a factor. 

How to build and install your own Septic Tank system

Firstly we recommend that you should not consider this unless you have extensive building or groundwork experience. The process is technically challenging and potentially dangerous. This septic tank installation guide, therefore, assumes a level of background knowledge. Okay, caveat over.

  • Planning, Design and Regulations

Are you likely to get the relevant planning permission for a septic tank replacement or new installation? It is likely that you will be required to install a sewerage treatment plant. Make yourself familiar with the governments’ general binding rules.  Contact the Environment Agency and discuss your planned project with them. You will also need to read and understand all of the relevant building regulations.

Next, you need to plan and design the site ensuring that the design adheres to all of the relevant regulations. There are four main sections. The pipe from your property to the Septic Tank, the Septic Tank, the connection to the soakaway/discharge and the soakaway/discharge.

We generally take some time to have a good look around the site. Check accessibility (for the Tank and Plant), often tanks are installed in the rear garden, if you can’t get a digger, dumper and tank hauler in then you need to know. You should then have a look at the space available.  Do you have enough room to fit the tank and soakaway and still meet building regulations? If replacing an existing system do you have enough space for a new soakaway? Alternatively, you can dig up and replace the existing one?

  • What tank and how big?

The Septic Tank System is normally designed based on the number of people in the house. You need to undertake a basic calculation to see how big a tank you will need to meet Environment Agency guidelines. Use this calculation and check out this useful information

Number of people x  150L + 2000L = minimum tank size required.

Also, consider the need for emptying and the relative costs. A smaller Septic Tank will need emptying more regularly. Again please see our guide

  • Soakaway or Drainage Field Design

You will need to consider the design of the soakaway or method of discharge. If you are installing a new or replacement discharge to ground it will have to conform BS 6297:2007.

 . Please see our blog on Drainage Fields.

Once you are happy with the design, logistics and have complied with all of the building regulations and have the relevant permissions you need to choose the right tank for you. You already know the minimum size you need. 

  • Installation

Then it’s onto the installation. If at this point you choose to get the professionals in, please get in contact. We would advise getting at least three quotes. Personally, I always judge the attitude and knowledge of the contractor as being as important as the price. If you still want to do it yourself my main advice would be twofold, make sure the system runs downhill and fill the tank with water before pouring on the cement.

  • Ventilation

Ventilation is also important to avoid the dreaded bad smell scenario. Ensure you have a vent on the tank and at the ends of the soakaway trenches. Also a well-designed soil stack on your building. Please see these two links for a general idea:


Venting to avoid smelly drains

  • Future Maintenance, Inspection and Repair

You also need to consider future maintenance. lids on the tank should not be covered over with soil. The tank should be within 30m of a driveway, septic tank emptying companies generally only have 30m long hoses for emptying tanks. You also need to consider taking out a maintenance contract. There is no point in expending all of this effort to have to do it again in two years. We offer maintenance contracts. Please visit our servicing page.

A Septic Tank Installation diagram and how a Septic Tank works

A Traditional Septic Tank, as shown in the adjacent image works using gravity. The Waste flows into the first chamber on the left where gravity pulls the heavy sludge to the bottom. Grease, Fats and Oil float to the top. The middle section is the cleaner wastewater, this then flows into the second chamber. In the second chamber, there is a further cleaning action as any residual sludge is separated. From the Second chamber, the waste then flows to your Drainage field or Soakaway. In former times this may have been directly discharged to a watercourse. 

As you may now appreciate from the diagram if you do not regularly empty your Septic Tank sludge will flow into the second chamber. This leads to blockages and problems with your soakaway. These problems will eventually damage the Septic Tank. 

How a Septic Tank works

As part of Septic Tank Installation in the UK it is a good idea for a customer to understand how a Septic Tank works

An introductory guide to Septic Tank Installation

This video is a good introduction in how to install a septic tank system and drainage field or soakaway. Although American we have included it to show the process more than specific regulations.

New Forest Philosophy

Our company is based in the New Forest Hampshire near the sleepy town of Fordingbridge. All of our engineers grew up in the area with many of us going to school together and being part of the same community. We are all conscious of our environment and share a love of the outdoors. This is why we specialise in environmentally friendly installations with low impact solutions. We operate throughout the south of the UK carrying the ethos of the New Forest with us.

We cover the whole Wiltshire, Hampshire, West Sussex, Somerset and Dorset. Serving the cities of Salisbury, Winchester, Southampton, Bournemouth and Basingstoke.  We started our company because after spending most of our lives working in the sector we grew tired of its money first attitude. We will not come out to sell extras. We will offer fixed price quotations and will not issue extra charges. We will not send a flash salesman in flash trucks. We will turn up and offer you the best price we can to ensure a quality installation. We will not cut corners. 

Homeseptic Ltd. is rated 4.8 out of 5 based on 28

Our reviews on Google
Google Reviews
Septic Tank Installation
Article Name
Septic Tank Installation
Our main page is devoted to Septic Tank installation and how our installers carry out the works.
Publisher Name
Homeseptic Ltd
Publisher Logo
Call Homeseptic