What is a Binding Rules

The Binding Rules, formally known as the General Binding Rules, are a set of legal standards introduced by the UK Government to regulate small-scale, non-mains drainage systems. These rules apply to privately owned sewage treatment systems, including septic tanks and small sewage treatment plants, and are designed to ensure that such systems do not pose a threat to the environment or public health.

Introduced by the Environment Agency in England in January 2015 under the Environmental Permitting (England and Wales) Regulations 2010, and revised in subsequent years, the Binding Rules are legally enforceable. Their main objective is to simplify the regulatory landscape for owners of domestic and small commercial properties, while providing a consistent framework for environmental protection.

By adhering to the Binding Rules, property owners can avoid the need to apply for an environmental permit—provided their system meets the specified requirements. However, failure to comply can result in enforcement action, fines, and mandatory system upgrades.

Scope and Application

The Binding Rules apply to any property in England or Wales that is not connected to the public sewer and instead uses a private means of sewage disposal. This includes:

  • Septic tanks discharging to ground via a drainage field. 
  • Small sewage treatment plants (also known as package treatment plants) discharging to ground or surface water. 
  • Cesspools or cesspits (though subject to separate regulations, not covered under the Binding Rules). 

The rules cover systems that treat domestic sewage from either:

  • A single property (such as a rural home, cottage, or smallholding). 
  • Multiple properties (e.g. a group of houses sharing a private treatment system). 
  • Commercial premises with low-volume domestic-type wastewater (such as offices or small shops). 

Systems serving up to 13 people (or up to a maximum daily volume of 2 cubic metres) fall under the general scope of the Binding Rules. For larger discharges or complex situations, an individual environmental permit is required.

Key Requirements of the Binding Rules

The Binding Rules outline a range of conditions related to the construction, use, maintenance, location, and discharge from private sewage systems. The most critical elements include:

1. Discharge Standards

Your system must:

  • Treat only domestic sewage. 
  • Not cause pollution to the environment. 
  • Discharge a maximum of: 
    • 2 cubic metres per day to ground, or 
    • 5 cubic metres per day to surface water. 

Systems exceeding these thresholds require a permit from the Environment Agency.

2. Location of Discharge

There are strict rules about where a system can discharge:

  • Discharges to ground must go via a drainage field (also called an infiltration system), not a soakaway pit, deep borehole, or ditch. 
  • Discharges to surface water (such as a stream, river, or ditch with year-round flow) are only permitted for small sewage treatment plants—not septic tanks. 
  • The discharge point must be located a safe distance from water supplies, buildings, and boundaries, such as: 
    • At least 10 metres from a watercourse or field drain. 
    • At least 50 metres from a drinking water supply, including private wells and boreholes. 

3. Septic Tank Restrictions

From 1 January 2020, septic tanks that discharge directly to surface water are no longer permitted. Property owners must:

  • Upgrade to a small sewage treatment plant, or 
  • Install a drainage field to discharge to ground, or 
  • Connect to the mains sewer (if within 30 metres), or 
  • Apply for a permit if none of the above is feasible. 

4. Maintenance and Servicing

Owners are responsible for ensuring their system is:

  • Maintained in good working order. 
  • Desludged (emptied) as often as recommended by the manufacturer or at least once a year. 
  • Serviced regularly by a competent person. 

Keep records of servicing and desludging, especially if selling the property.

5. New Discharges and Installations

If installing a new system:

  • The discharge must not cause pollution. 
  • A BS EN 12566-certified system must be used. 
  • Systems must be installed by a competent person in accordance with Building Regulations (Part H). 
  • A new discharge to surface water or ground must not be within 500 metres of a designated sensitive site (e.g. nature reserves or bathing waters). 
  • You must notify the Environment Agency if you plan to start a new discharge. 

Responsibilities of Property Owners

It is the responsibility of the owner or operator of the system (typically the property owner or landlord) to ensure compliance with the Binding Rules. In some cases, where multiple properties share a system, a legal agreement may be required to assign maintenance responsibilities.

Responsibilities include:

  • Regular inspections and timely desludging. 
  • Ensuring no illegal discharges (e.g. from garages, commercial kitchens, or surface run-off). 
  • Repairing or upgrading faulty systems. 
  • Providing documentation when selling the property. 

During a property sale, the seller must inform the buyer in writing about the existence, location, and maintenance of the sewage system. This includes service records and evidence of compliance.

Exemptions and Permits

If your system cannot comply with the Binding Rules—due to location, size, or discharge type—you must apply for an environmental permit from the Environment Agency. Examples include:

  • Discharges in a source protection zone. 
  • Sites within 400 metres of a designated shellfish water. 
  • Discharges to ground with unsuitable soil conditions. 
  • Systems serving commercial properties with industrial waste. 

The permitting process involves a more detailed assessment, and additional treatment or monitoring may be required.

Enforcement and Consequences of Non-compliance

The Environment Agency has the authority to inspect private sewage systems and take enforcement action where pollution or non-compliance is found. This may include:

  • Issuing an enforcement notice. 
  • Requiring the owner to upgrade or replace the system. 
  • Imposing fines or prosecution in serious cases. 
  • Restricting future use of the system. 

Routine inspections are often triggered by complaints, visible pollution, or changes in land use.

Relevance to Drainage Professionals

For plumbers, drainage engineers, and construction professionals, understanding the Binding Rules is essential when:

  • Advising clients on septic tank or treatment plant installations. 
  • Designing drainage schemes for rural or off-grid developments. 
  • Carrying out inspections or servicing work. 
  • Supporting property sales or legal conveyancing. 

Professionals should ensure all new installations meet the requirements of the Binding Rules and Building Regulations, and help property owners understand their legal responsibilities.

Summary of Common Mistakes

Some of the most frequent reasons for non-compliance include:

  1. Discharge from a septic tank directly to a stream or ditch. 
  2. Use of soakaway crates or deep boreholes instead of drainage fields. 
  3. Lack of regular emptying or maintenance. 
  4. Failure to notify buyers during property sale. 
  5. Inadequate documentation of servicing or repairs. 

Correcting these mistakes is often costly and time-consuming. Early awareness and compliance can avoid unnecessary problems.

Conclusion

The Binding Rules form a crucial part of the UK’s strategy to manage small-scale sewage systems in a way that protects water quality, public health, and the wider environment. For property owners, these rules provide a clear and practical framework for maintaining private systems responsibly. For drainage professionals, they offer guidance on designing and managing off-mains drainage in line with modern environmental standards.

As environmental concerns and regulatory expectations continue to rise, compliance with the Binding Rules is not just a legal necessity—it is a critical aspect of sustainable property management in the 21st century.