Sewage Treatment Plant Regulations in England: What You Need to Know

Many of the regulations around small sewage treatment plants in England are the same as septic tank regulations. Find out specific rules and laws about owning a tank or treatment plant here, and make sure you are in-line if you already own one or are prepared if you are planning to install one.

Building Regulations for Sewage Treatment Plants

Before a sewage treatment plant is even installed, the type you have chosen to install must be legal for sale and use in the UK. The standard for sewage treatment plant units designed for under 50 people in most of Europe is the EN12566-3 2005. This is also required for CE marking. CE marking is mandatory in the UK.

Plant units designed for fewer than 50 people also require the BS EN 12566-3 Certificate, which provides proof that a sewage treatment plant is:

  • Watertight
  • Structurally stable 
  • Durable
  • Has sufficient treatment capacity
  • Offers effective treatment for the development in which it is to be installed

Beyond this, you may also need to be aware of Building Regulations in relation to sewage treatment plants. The key points to take from these regulations are:

  • The unit must be installed more than 7m from a habitable property
  • The unit’s soakaway must be a minimum of 10m from a watercourse, 15m from a building, and 50m from a borehole or spring
  • The soakaway must be designed to BS6297: 2007 and all percolation test results must be submitted
  • The discharge point must be more than 10m from a habitable property
  • If the discharge is intended to soak away, a sampling chamber must be provided before the soak away
  • Drainage fields must be constructed in the aerobic soil layer, i.e. within 700mm of ground level

General Binding Rules and Regulations

The general binding rules are a list of regulations that all owners (or “operators”) of septic tanks and sewage treatment plants must follow once their system is installed. These came into effect from 1st January 2015, and were designed to simplify the laws controlling small sewage discharges from these types of private systems in England.

You can find full lists of the current rules, and the amendments that are due to go into effect from October 2023, on the UK government’s page about general binding rules for small sewage discharges in England.

General Binding Rules and Septic Tanks

On 1st January 2020, the general binding rules specifically in relation to septic tanks were updated. Anyone with a septic tank that allowed its sewage discharge to flow into a watercourse had to have it replaced or upgraded before that date came. For many, this meant a sewage treatment system was installed for their property.

Staying in Compliance

For property owners taking care of their septic tank or sewage treatment plant, staying in compliance with general binding rules is easy. All you have to do is:

  • Ensure your system is regularly emptied by a licensed waste carrier (this should happen at least once a year, or in accordance with the instructions of the manufacturer)
  • Maintain your system well and regularly, and ensure any problems are fixed as soon as possible
  • Limit discharge to 2,000 litres of treated sewage water per day when discharging to ground (a drainage field)
  • Limit discharge to 5,000 litres of treated sewage water per day when discharging to surface water (a flowing water surface like a stream)
  • Ensure you have a permit if you plan on discharging more than the amounts given above
  • Speak to the Environment Agency if you are planning on installing a new system, in case you need a permit
  • Speak to your local council and planning authority to check that your planned installation meets building regulations (only equipment that meets British Standard BS EN 12566 is permitted)
  • Inform the buyer in writing that the property has a septic tank or sewage treatment plant if you ever sell

If You Do Not Meet General Binding Rules

If the system you currently have doesn’t meet the general binding rules, you will be advised to make changes. For example, you might be advised to change the system you are currently using for the “next one up” or even higher in the list of acceptable systems.

For example, if you own a septic tank that doesn’t meet regulatory requirements, experts will first recommend that you find out if your property can be connected to a mains sewer (also called a “public foul sewer”). If an inspection reveals the connection isn’t viable, they will then strongly advise you get the tank replaced with a domestic sewage treatment system.

Failure to comply can result in a fine from the Environment Agency, and even prosecution.

Helping You Meet Regulations

Experience the expertise of our fully trained and qualified team, specialising in all types of private drainage systems. From sewage treatment plants to septic tanks and cesspits, we possess the knowledge to keep your system compliant with regulations. Benefit from our regular maintenance and attentive care, ensuring the longevity and reliability of your system. For a reliable professional service tailored to your private drainage needs, contact us today.

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