The General Binding Rules – What Home Buyers Often Don’t Realise

Many home buyers are unaware that private drainage systems in England are regulated by General Binding Rules, set by the Environment Agency. These general binding rules exist to protect local watercourses and apply to thousands of properties with a septic tank or sewage treatment plant. 

If the system serving your new home does not comply, you inherit the responsibility and the cost.

 

Why The General Binding Rules Matter When Buying a Property 

Over 500,000 UK homes rely on private drainage. If that system is non-compliant, you could face: 

• Enforcement action from the Environment Agency 

• A requirement to upgrade or replace the system before you can sell 

• Unexpected costs that could be significant

• Delays to property purchases or mortgage approvals 

A pre-purchase drain and sewage treatment system survey can identify these risks before you commit.

 

How do the General Binding Rules Affect Septic Tanks and Sewage Treatment Plants 

One of the most common compliance issues uncovered during home buyer surveys is the type of system installed. 

• Septic tanks are not permitted to discharge directly into surface water, such as streams, rivers or ditches 

• If a septic tank discharges to surface water, it is usually non-compliant and must be upgraded to a sewage treatment plant (STP) or redirected to a drainage field 

• Sewage treatment plants (STPs) provide a higher level of treatment than septic tanks and are suitable for discharging to surface water, whereas septic tanks are generally only suitable for discharging to soakaways or the ground.

Many older systems were installed before the rules were updated, meaning sellers may be unaware that their system no longer meets current requirements. 

 

Maintenance, Capacity and Hidden Risks 

The General Binding Rules also require systems to be: 

• Correctly sized for the property 

• Properly maintained and serviced in line with manufacturer guidance 

• Desludged regularly using a registered waste carrier 

If a property has been extended, converted, or occupied more heavily than intended, the system may no longer be suitable. These issues are not visible during a standard home survey but are commonly identified during CCTV drain inspections and STP surveys. 

 

Selling a Property? Ensure Your Drainage is Compliant 

If you’re selling a property with a septic tank or sewage treatment plant, it’s essential to ensure your drainage system complies with the General Binding Rules. This protects you from legal issues, delays, and unexpected costs. 

When preparing to sell, you should provide: 

• The type and location of the system 

• Maintenance requirements and service history 

• Evidence that the system operates within consent levels and meets the septic tank general binding rules 

Missing or incomplete records can cause delays, raise concerns with solicitors, buyers, and mortgage lenders, and may even require urgent upgrades. 

 

Looking Ahead in 2026:  What You Need to Know About Legal Requirements 

Although the new legal requirement has not yet been published, in 2026 it is expected that a home buyers’ drainage survey could become mandatory for properties with private drainage systems. Ensuring your septic tank or sewage treatment plant is fully compliant with the General Binding Rules now will help you stay ahead of potential changes and avoid last-minute compliance issues. 

Like other essential household systems, sewage treatment plants should be serviced at least once a year to maintain efficiency and compliance. 

Need more information? Contact our experts on 01634 201111.

 

How a Pre-Purchase Survey Protects You 

A professional pre-purchase drain and sewage treatment system survey checks: 

• Structural integrity of the drains 

• Flow and mapping of the drainage system 

• Potential blockages, damage or root ingress 

• Compliance with the General Binding Rules 

• Whether costly upgrades may be required 

This gives buyers clarity, leverage during negotiations, and confidence that they are not buying into future legal or environmental issues.

 

Speak to the Experts Before You Buy 

Willow Pumps can carry out a comprehensive survey, checking your drainage system, pipework, and flow, and provide a detailed report with recommendations. A professional survey not only gives peace of mind but also facilitates the sale process by demonstrating compliance to buyers, solicitors, and mortgage lenders. 

We have over 30 years’ experience in water, waste and pump systems, delivering a complete service from inspection to maintenance. Our trained and insured engineers use the latest CCTV equipment and specialist tools to deliver clear, reliable reports you can trust. 

With bases in Kent, Wetherby and a nationwide network, we offer dependable 24/7/365 support for homeowners, buyers and property professionals. 

Call us on 01634 201111 to find out more about how they could support.