Off-Mains Drainage — Septic Tanks & Sewage Treatment Systems

What is this service?

Is your property served by a septic tank or sewage treatment plant? Are you buying or selling a property with one of these systems? Has your solicitor or mortgage lender asked for proof of compliance? If so, you may be affected by the General Binding Rules (GBRs) for small sewage discharges. These regulations are a legal requirement in England and Wales and apply to most off-mains drainage systems.

What Are the General Binding Rules (GBRs)?

The GBRs form part of the Environmental Permitting Regulations and came into force on 1 January 2015. They are designed to prevent pollution from septic tanks and sewage treatment systems.

Key Requirements:

Discharge Limits — Up to 2m³/day to ground or 5m³/day to surface water without a permit
Pollution — Your system must not cause pollution, odour, or nuisance
Surface Water Restrictions — Septic tanks must not discharge directly to streams, ditches, or watercourses
System Standards — Systems must meet recognised standards (e.g. BS EN 12566)
Location Requirements — Minimum distances apply from buildings, watercourses, and boreholes
Maintenance — Systems must be regularly emptied and properly maintained
Permit Exemption — No permit is required if all rules are met

Recent Updates (October 2023)

Shared discharges must not exceed threshold limits
New systems require at least 50m separation from others
Connection to mains drainage is required where reasonably possible

Why You May Need a Compliance Survey

The only reliable way to confirm compliance is through a professional inspection. At Happy Drains, we assess:

The type of system installed (septic tank, treatment plant, cesspit)
Its condition, size, and location
Whether it is correctly installed and maintained
How and where it discharges
Any incorrect connections (e.g. rainwater into foul systems)

You'll receive a clear, professional report with practical recommendations — ideal for homeowners, buyers, solicitors, and lenders.

What Happens If Your System Is Not Compliant?

Non-compliance can lead to:

Delays or refusal during property sales
Mortgage issues
Enforcement action or fines
Environmental damage or liability

Common solutions may include:

Installing or upgrading a drainage field
Replacing with a compliant treatment system
Connecting to mains drainage (where feasible)

How it works

Book a survey

On-site assessment

We assess the type of system installed, its condition, size, location, and how and where it discharges.

Professional report

You receive a clear, professional report with practical recommendations — ideal for homeowners, buyers, solicitors, and lenders.

Recommended next steps

If work is needed, we advise on options such as installing a drainage field, upgrading to a compliant system, or connecting to mains.

When to call

Property served by a septic tank or sewage treatment plant

Buying or selling a property with off-mains drainage

Solicitor or mortgage lender requesting compliance proof

System hasn't been emptied or maintained recently

Bad smells or wet ground near your drainage system

Unsure whether your system meets current regulations

Frequently Asked Questions

Do I need to empty my septic tank regularly?

Yes — it must be emptied as often as necessary to prevent overflow and pollution (typically annually).

Can a septic tank discharge to a ditch or stream?

No — this has not been permitted since January 2015.

What's the difference between a cesspit and a septic tank?

A cesspit is sealed with no outflow and requires frequent emptying. A septic tank treats waste and discharges to a drainage field.

What if my system seems to work fine?

Even if it appears functional, you must still maintain it and be able to demonstrate compliance.

Do the rules apply in rural areas?

Yes — the GBRs apply regardless of location.

How do I prove compliance when selling?

A professional survey and maintenance records (e.g. emptying receipts) provide evidence.