General Binding Rules Explained

In short: the General Binding Rules (GBR) are a set of conditions, in force in England since 1 January 2015, that let most small septic tank and treatment plant discharges operate without an individual permit — provided they meet specific conditions. Meet the conditions and you’re covered automatically; fall outside them and you typically need a permit or a system change.

What counts as a “small sewage discharge”

The GBR apply to discharges that don’t go through a public sewage treatment works and stay within a daily volume limit: 2 cubic metres (2,000 litres) a day for a discharge to the ground, such as a drainage field, or 5 cubic metres (5,000 litres) a day for a discharge to surface water from a treatment plant. A typical household is well within both, so this covers most domestic septic tanks and treatment plants.

The core conditions

To be covered by the GBR without a permit, your system generally needs to:

• Discharge to a drainage field (for septic tanks) rather than directly to surface water, or discharge suitably treated effluent (for treatment plants) that meets the relevant standard
• Be located an appropriate distance from watercourses, wells, boreholes and property boundaries
• Not be within a groundwater Source Protection Zone 1 (a discharge to ground there needs a permit), or within 50 metres of a well or spring used for drinking water
• Not be within 30 metres of a public foul sewer you could reasonably connect to (for a single home, measured from any boundary of the property)
• Use a system that meets the relevant British Standard (BS EN 12566 for tanks and treatment plants, BS 6297:2007 for drainage fields), unless it was installed before 1983
• Be emptied at least once a year, or as the manufacturer advises, be properly maintained and not cause pollution

Update in July 2026: engineered ground

On 23 July 2026 the Environment Agency updated its guidance on discharges to the ground. Where the natural soil drains too quickly for a drainage field, the ground can now be engineered to slow the rate water soaks through it, and a discharge to that engineered ground can meet the GBR as long as:

• it isn’t in a floodplain
• the engineered ground has a percolation value (Vp) of at least 15
• it’s located, designed and built in line with all the other recommendations in BS 6297:2007

This helps sites on very free-draining ground, such as sand or gravel. A percolation test is how the Vp is measured.

GOV.UK has also dropped the old “Rule 1” to “Rule 9” numbering from these pages, so the rules now appear as plain headings. If an older survey or report refers to a rule by number, the content of the rules is what counts.

The most common way people fall outside the GBR

By far the most common issue is a septic tank (not a treatment plant) discharging directly to a ditch, stream or other watercourse — septic tanks don’t treat effluent thoroughly enough for this to generally be permitted. See our dedicated guide: septic tank discharging to a ditch.

What happens if you don’t meet the conditions

You’ll typically need to either bring the system into compliance (adding a drainage field, or upgrading to a treatment plant) or apply to the Environment Agency for an individual permit. See non-compliant septic tank for what this looks like in practice.

Do the General Binding Rules apply everywhere in the UK?

No — they’re specific to England. Scotland (via SEPA), Wales (via Natural Resources Wales) and Northern Ireland (via NIEA) have their own, broadly similar but not identical, regulatory frameworks.