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Septic Tank Drainage Regulations in the UK

Septic Tank Drainage Regulations in the UK


All the information surrounding septic tank installation rules and regulations can be difficult for homeowners to understand. So, in this article we will outline all the septic tank regulations in the UK, what they mean for you, and how you can ensure your septic tank is up to standard.

When having a septic tank installed, your first step should always be to contact a reputable professional. An expert will help determine the best septic tank solution for your home and what it might cost you.

How Does a Septic Tank Work?

The purpose of a septic tank is to treat the waste water from your property. Septic tanks are commonly large structures made of brick, concrete, stone, or plastic and are most commonly buried underground not far from your home.

Septic tank

A septic tank works by separating the liquids and solids in your waste using gravity. The sewage flows into the tank and all heavy solids (otherwise referred to as ‘sludge’) sink to the bottom of the tank, while light solids (such as oils and grease) float to the surface. Some of the sludge is broken down by a naturally-occurring bacteria before the liquid effluent is discharged out of the tank and into a drainage field.

New Tank Legislation and Regulations

On 1st January 2020, new rules are being enforced regarding tanks to ensure these systems are as environmentally friendly as possible. These rules enforce the hygienic, safe, and eco-friendly disposal of all waste discharged from septic tanks, ensuring there is no pollution to the environment or risk to your health.

Your Septic Tank, Your Responsibility

The quality and hygienic impact of your waste disposal on the environment is completely your responsibility. Any pollution caused by your septic tank draining into a fresh water source, such as a river or stream for example, you could be liable for. You are also responsible for ensuring:

  • Your septic tank is properly maintained
  • Your septic tank access lids are secure and in good working order
  • Any drains leading to and from the septic tank, including the soakaway, are free-flowing and free from blockages.
  • If your septic tank is not regularly maintained in the proper way, it may fail and cause foul odours, flooding, pollution, and other health risks.

Septic Tank Emptying by Licensed Professionals

Septic tanks must only be emptied by licensed waste disposal companies. Unfortunately, they cannot be emptied by a local farmer or experienced member of the public. It is illegal in the UK for anyone, other than a licensed waste disposal company, to empty waste from septic tanks.

Please note: sewage waste should never be spread onto farmland as it poses a significant health risk for animals and will cause severe crop contamination.

Discharging Waste into Surface Water

Pipe discharging into water

Discharges into surface water that come directly from septic tanks are not allowed under general binding rules. If you have a septic tank that is discharging directly into surface water you will need to have your system replaced or upgraded by 1st January 2020, or before if you’re selling your property.

If the Environment Agency finds out that your septic tank is discharging onto surface water, you will be causing significant pollution and will, therefore, have to replace or upgrade your system earlier than 1st January 2020. Usually, you will have to do this within one year, although agreements do vary on a case-by-case basis. Alternative options mean you may be able to:

  • Connect to the mains sewer (if and where available)
  • Install a drainage field so that the septic tank can discharge directly into the ground instead.
  • Replace your septic tank with a small sewage treatment plant.
  • You can apply for a permit to discharge sewage into surface water (however, permits are only granted in exceptional circumstances).

Regulations for Septic Tank Installation

All septic tank installation procedures should be carried out by a professional so that all requirements and relevant legislations are followed. To ensure the regulations are followed when installing your septic tank, the two bodies that must be contacted are the local authority building control and the environment agency. These institutions will give all the advice and guidance needed as to where a treatment plant and discharge point or soakaway must be situated.

If you’re installing a brand-new septic tank system on your property, you must have the following:

  • Planning permission
  • Approval from building regulations

The Current Standards for New Systems:

The installation standards for new system requirements are as follows:

  • BS EN 12566 for small sewage treatment plants.
  • BS 6297:2007 for drainage fields

Your treatment plant will have met the British Standard at the time of installation if it has the following:

  • It has a CE mark
  • The manual or other documentation that came with your tank or treatment plant has a certificate of compliance with a British Standard.
  • It is on British Water’s list of approved equipment.

One of the most important installation regulations is that your treatment system must be installed properly and have enough capacity to serve your requirements. That is, your treatment system must be big enough to comfortably the maximum amount of sewage it will need to treat.

If the sewage in your system increased because you’ve extended your property, connected to another property, or now have more people living in your home, you must ensure the treatment system is still big enough.

However, if your property is situated only 30 metres away from a mains sewer line, the Environment Agency will require you to connect to the mains system rather than installing a sewage treatment unit.

Do You Need Planning Permission for a Septic Tank?

In some areas of the UK, a treatment plant may require planning permission. If the plant is being installed as part of a new build project, permission is definitely required. However, it is worth noting that many planning approval documents will write that your septic tank installation is ‘subject to EA/SEPA approval’. Do not panic at the use of language, all this means is that a response is required from the Environmental Agency before your installation is given full planning permission.

Who Should Install Your Septic Tank?

Septic tanks should always be installed by a team of experienced and qualified professionals. This will ensure that all appropriate precautions and procedures are observed to avoid any potential accidents. Installation close to trees and shrubbery is not recommended, however, a professional will know all of this and ensure your septic tank is installed in an appropriate area, to a high standard, and with all safety precautions in place.

Find Out More about Septic Tank Laws

If you would like to find out more about septic tank drainage regulations in the UK, visit the septic tank regulations page on the Gov.uk website. Alternatively, call our septic tank specialists at Coastal Drains. We have worked hard to collate all the information you need about the new regulations and we would be more than happy to answer your questions.