Septic tank regulations 2020


Septic tank regulations for both England and Wales have changed on January 1, 2020. All septic tank types that discharge to surface water now require either upgrading or replacement with a sewage treatment plant. This article is about Septic Tank regulations 2020.

Are you affected? Let’s see what does the regulation apply to: 

The Septic Tank regulations 2020 applies to:

  • England and Wales
  • Septic tanks discharging directly into a watercourse
+44 (0)1934 422 311

If you have any questions, feel free to call us

Share on Facebook
Share on LinkedIn

Backgroung information about the Septic Tank regulations 2020

As of January 1, 2015, new rules relating to sewage treatment discharge came into effect.

Since 2015, all septic system discharging directly to water are illegal, such as:

  • To surface water
  • into rivers
  • To streams

If you are in a situation such as those listed above, you will have to upgrade your existing septic tank to align with the new environmental rules.

2020 was the deadline by which you have to update, or replace, your sewage treatment plant if it does not align with the regulations outlined under the Environment Agency’s “General Binding Rules”.

The regulations are in place in both England and Wales in order to prevent any water pollution as a result of wastewater.

Who is responsible for Septic Tank regulations 2020 ?

Under the code of practice by the Environment Agency, the homeowner is responsible for:

  • the installation
  • the maintenance
  • and impact that the property’s sewage system may have on the environment

What is the difference between a Drainage Field and a Waterway?

For a better understanding of the 2020 septic tank regulations, we will see the difference between both:

Dos icon

​Drainage field

In this case, the wastewater is released through a network of pipes in surrounding subsoils, providing an additional form of treatment for the effluent from the septic tank.
This helps ensure that the sewage water being dispersed does not cause pollution.

Septic tanks discharging into a drainage field are not affected by 2020 septic tank regulations.

Donts icon


The effluent flows through a pipe directly into a stream, a river or a lake, following the general binding rules about a small sewage discharge to surface water.
The new rules do affect the direct discharge to a waterway, as they state that direct discharge from a septic tank into a watercourse will no longer be permitted.

You must upgrade your system.

Regulations for existing and new sewage treatment systems

In this section, we will examine how the implementation of these new septic tank regulations will impact pre-existing septic tank units as well as new installations.

First identify your type of installation:

  • If your system was installed and discharging prior to this date (01/01/2015), you have what is called an ‘existing discharge’.
  • Whenever it was installed and discharging after this date, you have a ‘new discharge’.


Treatment system options:

If you are discharging directly into a watercourse, such as a river or a stream, you are required to use a small sewage treatment plant (a.k.a. package treatment plant). This uses mechanical parts to clean the wastewater so that it does not pollute the river or stream.

People who are discharging to surface water have been given three options:

  1. Connect to the main sewer. However, this is unavailable in a lot of remote areas.
  2. Install a drainage field. This is also known as an infiltration system and allows the septic tank to discharge to the ground instead of the surface water. Do note that, in many cases, the installation of a drainage field is not possible due to site constraints such as space and/or the soil not having sufficient drainage potential such as clay soil.
  3. Upgrade the septic tank with a small sewage treatment plant, eliminating the need for any drainage field. The Tricel Novo would suit this situation perfectly. It is a reliable, cost-effective solution that will allow you to comply with environmental legislation.

The timeframe for new septic tank regulations


Under new guidelines, the upgrade to your sewage treatment system must now be in place.

If the Environmental Agency or Natural Resources Wales finds that you are currently polluting surface water as a result of discharge from a septic tank, you will be required to install a new system.
Generally it will be given one year to upgrade, although this will be done on a case-by-case basis.

For a full listing of how the 2020 regulation changes to the septic tank regulations may affect you, download your free 2020 Septic Tank Regulation Handbook today!

Tricel's solutions to meet with the 2020 septic tank regulations:

Option 1: Replace your septic tank by a Tricel Novo sewage treatment plant.

A great product for homeowners.

Reliable, easy to install and maintain, an ideal solution if you do not have much installation space for your treatment system.

The Novo is the most cost-effective of our products designed specifically for homeowners.

Compliant with the 2020 regulations

Option 2: Install a Tricel Puraflo

An ideal product for environmentally sensitives sites, the peat fibre (100% natural) is perfect for treating your domestic wastewater.

It dramatically reduces the risk of pollution from your domestic treatment plant.

The Puraflo is the ideal product for holiday homes.

Compliant with the 2020 regulations

What to do next?

If you are affected by the 2020 septic tank regulations, contact us to book your site visit, request a quote or advise you on the best course of action for your project.

Required regulatory standards for systems

Your sewage treatment system is in the obligation to be of a standard under these new septic tank regulations.

For small sewage treatment plants, the standard is BS EN12566. This standard consists of seven main parts:

For drainage fields, the standard is BS 6297:2007.

Capacity dependent upon requirements

Please note: When installing a new sewage treatment plant, you must check with “British Water Flows and Loads 4 guidance” to ensure that it meets sizing requirements. Your treatment system must be able to handle the largest amount of sewage that it will need to treat.

Regulating agencies

For England and Wales, visit the Environment Agency’s and Natural Resources Wales website to read the General binding rules: small sewage discharge to a surface water.

Different rules apply for Northern Ireland and Scotland, check with the following authorities for further details: the Scottish Environment Protection Agency or Department of Agriculture, Environment and Rural Affairs if your property is located in Northern Ireland.

Part 1: Prefabricated septic tanks – requirements and best practices for these units.

Part 2: Soil infiltration systems – discusses the design parameters, building specifications and implementation.

Type 3: Packaged and/or assembled domestic sewage treatment plants – the requisites and testing techniques used to gauge packaged sewage treatment plants that are necessary to treat sewage to the required quality.

Part 4: Septic tanks assembled in situ from prefabricated kits – the standards and measurement sizes, including resistance to water leaks, pipe dimensions and grading of conformity.

Part 5: Pre-treated effluent filtration systems – a guide discussing design parameters, building information and component requisites for treating effluent.

Type 6: Prefabricated treatment units for septic tank effluent – the requirements, testing practices and grading of conformity for prefabricated secondary treatment units.

Part 7: Prefabricated tertiary treatment units – the requirements, testing practices and grading of conformity for a packaged and/or site assembled tertiary treatment unit.

Additional rules for systems installed and in use on or after January 1, 2015

Tricel Novo 8PE domestic sewage treatment plant - how does a domestic wastewater treatment plant work
These regulations apply to you if you:
  • started a new discharge from a small sewage treatment plant on or after January 1, 2015.
  • had a discharge to the ground before January 1, 2015, which you now want to change to discharge to surface water (or the other way around)

If you are within 30m to a public sewer, then you will not be allowed to start a new discharge from your sewage treatment plant. For developments and multiple properties, this distance is multiplied by the number of properties. For example, if there are four properties, the distance is increased to 4 x 30 meters = 120 metres.

If there is a valid reason prohibiting you from connecting to the public sewer and use a sewage treatment system instead, you must apply to the Environment Agency for a permit.

You are required to have planning permission and Building Regulations approval if you have or are planning to install a new sewage treatment plant.

You must apply for a permit if you want to begin a new discharge to surface water in or within 500m of a designated sensitive area. A sensitive area includes special conservation sites, designated bathing water, protected shellfish water or special protection areas. You also need a permit if the discharge is within 200m of an aquatic local nature reserve, or within 50m of a chalk river or aquatic local wildlife site.

You must contact the Environment Agency to check if you are in or near a designated sensitive area.

Your new discharge must go to an area that has water flow year-round. It will not be allowed the flow to watercourses that seasonally dry up.

A partial drainage field is a system for discharging water, which allows effluent to drain into the ground when levels in the watercourse are low, and into the watercourse when groundwater levels are high. A partial drainage field can only be used with a small sewage treatment plant and must be within 10m of the edge of the watercourse.

Frequently Asked Questions

Domestic wastewater includes graywater from sinks, showers, baths, and toilets, as well as sewage from toilets. Rainwater is not classified as grey water and should be directed to a soakaway.

You may need a ‘consent to discharge’ permit from your local building control department.

Once you discharge it, water must either flow into a drainage field or into a running watercourse. Direct discharge would fail and block up quickly, in addition to violating the government’s General Binding Rules for small sewage discharges.

Get in touch