NBS Source

General Binding Rules 2020


2020 General Binding Rules

For decades, millions of septic tanks have been installed throughout the UK in rural and urban areas. Septic tanks are known to be ineffective at processing sewage to modern environmental standards, causing long-term damage to the country’s natural water infrastructure and wildlife.

It was therefore inevitable that new rules and a code of conduct would be introduced to prevent the effects of wastewater pollution once and for all; The Environmental Permitting (England and Wales) (Amendment) (England) Regulations 2014 came into force on 1 January 2015 creating the General Binding Rules (GBRs) for septic tanks or small sewage treatment plants for domestic use. These rules are designed to reduce the level of pollution from sewage in the nation’s watercourses.

The rules state that any existing septic tank discharging to surface water, ie, to a water ditch, stream or river, etc, must have been upgraded or replaced with a new package sewage treatment plant by 1st January 2020.  

Failure to comply can incur significant fines from the Environment agency and delays in selling impacted properties.


Current methods of discharging wastewater from septic tanks

Previous to the General Binding Rules, wastewater from septic tanks was typically discharged in the following two ways:

Drainage field

Wastewater is released through a network of pipes in surrounding sub-soils, providing an additional form of treatment for the waste from the septic tank. This helps to ensure that the wastewater being dispersed does not cause pollution.

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

Directly to surface water

Wastewater flows through a pipe directly into a stream, river or lake. 

Binding rules state that direct discharge from a septic tank into a watercourse is not permitted.

So, what are your options?

1. Connect to the main sewer

This may not be possible in remote locations, although pump chambers can be used to direct wastewater to the mains sewer.

2. Install a drainage field

(Designed in accordance with BS6297)

This allows the septic tank to discharge wastewater into the ground instead of surface water. 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 (ie, rock, clay, high water table).

3. Install a Uni:Gem septic conversion unit

A Marsh Uni:Gem can be installed and connected to a pre-existing septic tank. This treats the wastewater to a sufficient quality allowing it to be discharged to surface water. See below for further detail.

4. Upgrade your septic tank to a Marsh sewage treatment plant

This eliminates the need for a drainage field and ensures that the wastewater is fully treated before being discharged. Options include the Ensign, Ensign Shallow and Ultra Poylok L.


Marsh Industries, the leading UK manufacturer of package sewage treatment plants, produces over 3000 units per year. However the company’s range of Uni:Gem★ septic conversion units is the only product available on the market which can treat wastewater from an existing septic tank without the need for a complete replacement product or drainage field upgrade.

To comply with the GBRs and current EN standards, the entire Uni:Gem range was redeveloped from the ground up and tested, not only to meet, but to exceed UK and International standards. The Uni:Gem★ was born – creating an ‘industry first’ 2020 compliant septic conversion unit with outstanding processing performance.

The Uni:Gem★ range was tested in accordance with BSEN12566-3/A1:2009 and EN12566-6 standards at the PIA GmbH test facility in Aachen, Germany, over the course of 38 weeks with a daily loading of:

Flow: 900 litres/day BOD: 360g NH4: 48g

Testing occurred between November 2018 and August 2019 to ensure all seasons were covered whilst minimum/maximum temperatures were tested to assure Ammonia and BOD process reduction for the UK climate. Holiday periods were also simulated during the test procedure. Final test results yielded an output of 12.5:16:4mg/ltr (BOD:Suspended solids:Ammonia) that is well within national discharge consent requirements.

The Uni:Gem★ is an extremely cost effective solution for converting any polluting septic tank into a fully compliant sewage treatment plant ensuring homeowners, estate managers, water companies/amenities have an effective way to keep the environment clean whilst providing a quick and efficient installation process.

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