Is your septic tank compliant?

10.01.2023

Everything you need to know about the updated General Binding Rules

The General Binding Rules (GBRs) are the legal standards that regulate small sewage discharges from septic tanks and sewage treatment plants in England. The General Binding Rules (GBRs) 2015 were implemented on January 1, 2015, to govern small sewage discharges in England. They set out requirements for small sewage discharges, including that new systems must not discharge untreated sewage into open water and must use a septic tank or small sewage treatment plant. Identifying that for discharges to surface water, a small sewage treatment plant would be required, while septic tanks would need to discharge to a drainage field in the ground. 

These rules were then further tightened in 2020 - most notably banning existing septic tanks from discharging directly into surface water. Owners with such systems had to upgrade or replace them by this date, or by the time they sold their property if that came first. These rules also include general requirements for septic tanks and sewage treatment plants, such as correct installation, regular maintenance, and regular emptying. 

In 2023, further clarification and enforcement updates have been made with reference to combined discharge and distances between discharge points. Homeowners, property buyers, sellers, and installers should ensure their systems remain compliant to avoid pollution, legal issues, and costly last-minute upgrades.

Below is a breakdown of what has changed - and how Marsh Industries can help you stay on the right side of the rules.

What’s changed in 2023?

While the core 2020 rules still apply, the 2023 update strengthened enforcement, responsibility, and evidence requirements:

1. Increased enforcement around surface water discharges
   Regulators are now actively checking rural and semi-rural areas for systems that still discharge directly to streams, rivers, ditches, lakes, or coastal waters.
2. Under the 2023 update, no septic tank may discharge directly to surface water under any circumstances.
3. Greater emphasis on proving compliance
   Homeowners are now expected to provide documented evidence of compliance when:
   • Selling a property
   • Refurbishing or extending a property
   • Replacing or upgrading off-mains systems
   • Responding to an Environmental Health query
   This includes showing how wastewater is treated, where it discharges, and when the system was last serviced.
4. Responsibility extends to new property owners
   Buyers inherit the legal responsibility for any non-compliant system.
5. The 2023 update stresses that sellers must disclose the type of system installed and confirm whether it meets current regulations.
6. Drainage fields must meet BS 6297
   Where a drainage field is used, it must be designed and installed in accordance with BS 6297.(link to web definition of the standards)
7. Many older soakaways no longer meet this standard, meaning assessment or replacement may be required.
8. Sites with limited space face stricter scrutiny
   If a drainage field is not feasible (e.g., clay soils, high water table, small plots), the system must be upgraded to a sewage treatment plant (link to sewage tp page) or an approved conversion unit.(link to uni-gem page).  In doing so creating an acceptable level of effluent discharge to surface water.

Current compliant discharge options (2023)

If your septic tank currently discharges to surface water, the law requires you to upgrade.

The 2023 rules allow the following compliant options:

1. Connect to mains sewer (where possible)
If access to a public sewer exists, connection is the simplest compliant option.Pump chambers can be used if the site is low-lying.

2. Install a drainage field (BS 6297 compliant)
This allows treated wastewater to percolate safely into the ground.However, with space or percolation constraints this option is not suitable for all sites.

3. Install a septic conversion unit such as the Uni:Gem
A compliant solution where the existing septic tank can be retained.A conversion unit treats effluent to a high enough standard to discharge to surface water.  The appropriate functionality  of the existing septic tank and its ability to treat the relevant flows and loads should be taken into account.

4. Upgrade to a full sewage treatment plant
This is the most common route.A modern treatment plant treats wastewater to a much higher standard and removes the need for a drainage field.

How Marsh Industries can help you meet the 2023 rules

Marsh offers a range of off-mains solutions - from small domestic systems to large commercial plants - ensuring full compliance with the General Binding Rules.

✔ Marsh Ensign Sewage Treatment Plants

• Tested and approved to BS EN12566-3/A1:2009(link)
• High treatment performance (97% pollutant removal)
• Available in Ultra, Standard and Shallow variants
• Suitable for 4–50PE applicationsA reliable and economical long-term solution for complete replacements.

Marsh sewage treatment plants

✔ Marsh Ultra:Polylok L

• Innovative, compact domestic treatment plant
• High performance: 20:30:20 effluent quality
• Available in 6PE and 12PEIdeal for sites needing fast, straightforward installation.

Marsh Ultra:Polylok L

✔ Uni:Gem Septic Conversion Unit

• Converts an existing septic tank into a compliant treatment system
• Suitable for domestic, commercial, and agricultural applications
• Allows continued discharge to surface waterPerfect where a drainage field or full system replacement isn’t feasible.

Marsh Uni:Gem septic conversion unit

Need help achieving 2023 compliance?

Marsh Industries provides complete off-mains wastewater solutions and can guide you through every stage - from assessment to installation.

📞 Call us: 01933 654582 | Email: sales@marshindustries.co.uk