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Overview

If youre the operator of a septic tank or small sewage treatment plant, you will not need a permit if you meet all of the general binding rules that apply to you.

The full set of rules is given in the publication Small sewage discharges in England: the general binding rules.

This guide explains which of the rules you must meet if you discharge waste water to the ground.

You must also have the other permissions that you need to discharge to the environment legally, including:

• appropriate building regulations approval
• planning permission, where necessary

Theres separate guidance on how to meet the general binding rules if your septic tank or small sewage treatment plant discharges to a surface water.

Work out which rules apply to you

The general binding rules you must meet depend on when your discharge to ground started.

Existing discharges that started before 1 January 2015

Youre in this category if all these points apply:

• the discharge was already happening before 1 January 2015
• you have not changed the discharge from surface water to ground
• you have not moved the location of the discharge or, if you have, it is still within 10 metres of the previous location
• you have not changed the volume of the discharge or, if you have, its not more than 2 cubic metres (2,000 litres) to ground

If you have replaced your treatment system but all these points apply, youre still in this category.

If so, you must meet therules that apply to all discharges. (Not the additional rules.)

Existing discharges that started on or after 1 January 2015 but before 2 October 2023

Youre in this category if, on or after 1 January 2015 but before 2 October 2023, you:

• started a discharge from a septic tank or small sewage treatment plant
• changed your discharge from surface water to ground
• moved the location of the discharge to more than 10 metres away from the previous location
• changed the volume of the discharge to more than 2 cubic metres (2,000 litres) a day to ground

If so, you must meet the:

• rules that apply to all discharges
• additional rules for discharges that started on or after 1 January 2015

New discharges that started on or after 2 October 2023

Youre in this category if, on or after the 2 October 2023, you:

• started a discharge from a septic tank or small sewage treatment plant
• changed a discharge from surface water to ground
• moved the location of the discharge to more than 10 metres away from the previous location
• increased a discharge to ground to more than 2 cubic metres (2,000 litres) a day to ground

If so, you must meet the:

• rules that apply to all discharges
• additional rules for discharges started
• additional rules for new discharges started on or after 2 October 2023

Rules that apply to all discharges

Rule 1: only discharge 2 cubic metres or less a day in volume

For sewage from a residential property, use the daily discharge calculator to work out how much you discharge a day.

For commercial properties (such as a hotel, restaurant or office) or holiday accommodation (such as a cottage or chalet), use British Waters Flows and Loads guidance. You will need to add all sources of flow together.

If you discharge more than 2 cubic metres (2,000 litres) a day to ground you must connect to the public foul sewer when its reasonable to do so. You must apply for a permit if its not.

Rule 3: only discharge domestic sewage

The sewage must be domestic in nature. For example, from a toilet, bathroom, shower or kitchen of a house, flat or business (such as a pub, hotel or office).

Find out more about what the definition of domestic sewage includes.

Rule 4: do not cause pollution of surface water or groundwater

The sewage must not cause pollution find out how to check for pollution.

Rule 5: use the correct treatment system

You must use a septic tank or a small sewage treatment plant to treat the sewage and then discharge the waste water to ground through a drainage field. You must not discharge effluent from a septic tank to a watercourse.

A septic tank is an underground tank where the solids sink to the bottom, forming a sludge, and the waste water flows out to a drainage field.

A small sewage treatment plant, also known as a package treatment plant, works in a similar way to a septic tank. But it uses mechanical parts to treat the waste water to a higher standard before it goes to a drainage field.

A drainage field, also known as an infiltration system, is a series of pipes with holes placed in trenches. These are arranged so that the waste water can trickle through the ground for further treatment.

The system you use must meet the relevant British Standard (see rule 9).

Discharges through drainage mounds can meet the general binding rules if:

• they are not in floodplains
• they are located, designed and constructed in line with the recommendations in British Standard BS 6297:2007

If you use a non-standard system (such as a well, borehole and soakaway)

You cannot meet the general binding rules if youre using:

• a well or borehole to discharge waste water to ground
• a soakaway (designed for draining rainwater) installed after December 2007

Instead you must either:

• upgrade to a drainage field that meets British Standards (see rule 9) and check whether you meet the other general binding rules that apply to you
• connect to the public foul sewer when its reasonable to do so you must apply for a permit if its not

You should avoid using non-standard systems such as boreholes, shafts, concrete rings or similar structures for new discharges to ground. These are not usually appropriate ways of disposing of sewage effluent because of their increased risk of pollution.

If your sewage effluent discharges directly to groundwater (at any time of year) through any of these non-standard systems:

• the Environment Agency will not grant you a permit
• you must replace this with a correct treatment system

This is explained in section G of the Environment Agencys approach to groundwater protection.

Rule 7: make sure the discharge is not in a groundwater source protection zone 1

To prevent groundwater pollution you must check if the discharge point is in a groundwater source protection zone 1 (SPZ1).

A groundwater SPZ1 can be the area around a commercial water supply used for drinking water or food production. To check if your discharge is in the inner zone (zone 1) you can either:

• use 