Septic tanks and sewage treatment plants: what you need to do

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1. Overview

You are responsible for (the 鈥榦perator鈥� of) a septic tank or sewage treatment plant if:

  • you own the property that uses the system
  • your property shares the system with other properties (you are jointly responsible)
  • you have an agreement with the owner of the property that you are responsible for the system, for example you鈥檙e renting and it鈥檚 in your tenancy agreement

If you connect your sewage system to the mains sewer (also called a 鈥榩ublic foul sewer鈥�) you do not need to do anything else and will not need a permit.

Your septic tank or treatment plant will treat your sewage and release liquid (鈥榮ewage discharge鈥�) into the environment. What you must do depends on:

  • whether the sewage discharge goes into the ground or into surface water
  • if the treatment system was installed or was changed significantly before 2 October 2023 (an 鈥榚xisting discharge鈥�)
  • if the treatment system was installed or has changed significantly since 2 October 2023 (a 鈥榥ew discharge鈥�)

There are different rules if you have a cesspool.

There are different rules for septic tanks and treatment plants , , and .

Sewage discharges

A sewage discharge is where you release sewage to either:

  • the ground (for example in your back garden)
  • surface water (for example a river, stream, estuary, lake, canal or coastal water)

New discharges are ones that started or changed significantly since 2 October 2023. Check what counts as a new discharge and what to do if you have one.

Existing discharges are from systems installed before 2 October 2023 that have not changed significantly since then. Check what counts as an existing discharge and what to do if you have one.

2. Your property has a new discharge

There are things you must do if your property has a 鈥榥ew discharge鈥� where you release sewage to the ground or to surface water.

You have a new discharge if one or more of the following apply:

  • it has not yet started (for example, if you鈥檙e still in the planning stage of building a house or business)
  • it started on or after 2 October 2023
  • it changed in type (from ground to surface water, or the other way around) on or after 2 October 2023
  • it has moved more than 10 metres on or after 2 October 2023
  • since 2 October 2023 the discharge has increased to more than 2 cubic metres (2,000 litres) a day if it goes to ground or more than 5 cubic metres (5,000 litres) a day if it goes to surface water

If you buy a house that already has a septic tank or sewage treatment plant, check when it was installed to work out if it counts as new or existing.

Connect to a public foul sewer

If you have a new discharge it must be connected to a mains sewer (also called a 鈥榩ublic foul sewer鈥�), if the Environment Agency decide it is 鈥榬easonable鈥� to do so.

Read the guidance on 鈥榙ischarges in sewered areas鈥� to find out which criteria apply when connecting different types of property to a public foul sewer.

The Environment Agency will decide what鈥檚 reasonable based on:

  • how close you are to a public foul sewer
  • the cost of connecting to a public foul sewer compared with the cost of installing a sewage treatment system
  • whether there鈥檚 anything in the landscape that would stop you connecting to the public sewer - for example a large road
  • whether your sewage treatment system would have any environmental benefits - for example if it reuses treated effluent

The Environment Agency will not give you a permit for a sewage treatment system if it鈥檚 reasonable for you to connect to the public foul sewer.

If it鈥檚 not reasonable to connect to a public foul sewer you鈥檒l need to install a sewage treatment system to deal with your sewage.

Installing a new sewage treatment system

You should only install a sewage treatment system if it鈥檚 not reasonable to connect to a public foul sewer.

You must have building regulations approval to install a new sewage treatment system.

You might also need to get planning permission. Check with your local council.

Check if you meet the general binding rules

If you already have or are installing a septic tank or treatment plant, and it is not reasonable to connect to a public foul sewer, check if it meets the 鈥榞eneral binding rules鈥�.

If you do not meet the general binding rules

You must try to meet the general binding rules, for example by changing your sewage treatment system.

If you cannot meet the general binding rules you must apply for a permit.

3. Your property has an existing discharge

There are things you must do if your property has an existing discharge where you release sewage to the ground or to surface water.

You have an existing discharge if it started before 2 October 2023 and all of the following apply:

  • it has not changed in discharge type (from ground to surface water, or the other way around)
  • it has not been moved more than 10 metres from the original location
  • the discharge has not increased in volume since 2 October 2023
  • if the discharge has increased it is still less than 2 cubic metres (2,000 litres) a day if it goes to ground or less than 5 cubic metres (5,000 litres) a day if it goes to surface water

Check if you meet the general binding rules

If you already have a septic tank or sewage treatment plant check if it meets the 鈥榞eneral binding rules鈥�.

If you do not meet the general binding rules

If your sewage treatment system does not meet the general binding rules, you must either:

  • connect to a public foul sewer if it鈥檚 鈥榬easonable鈥� to do so -
  • change your system so that it meets the general binding rules

If you cannot do either of these things, you must apply for a permit.

If you did not get planning permission or building regulations approval

If your current system did not get building regulations approval when it was installed, you may need to apply for it. You might also need planning permission.

If your system was installed before 1 January 2015, contact your local council for advice on planning permission.

4. General binding rules for septic tanks and small sewage treatment plants

You must make sure your system meets the 鈥榞eneral binding rules鈥� if you鈥檙e responsible for (the 鈥榦perator鈥� of) either:

  • a septic tank (an underground tank where the solids sink to the bottom and the liquid flows out and soaks through the ground)
  • a small sewage treatment plant (also known as a 鈥榩ackage treatment plant鈥� - a system that treats the liquid so it鈥檚 clean enough to go into the ground or a surface water)

If you meet the general binding rules, you do not need a permit.

Check if your discharge is domestic sewage

The general binding rules only apply to domestic sewage - for example from a toilet, bathroom, shower or kitchen of a house, flat or business. Find out what counts as domestic sewage.

If your discharge is not domestic sewage you must apply for a permit.

Check which rules to follow

The general binding rules vary depending on where you release (鈥榙ischarge鈥�) sewage and when the discharge started. Find out about the:

Ask your local installation or maintenance company if you鈥檙e not sure what sort of system you have.

If you do not meet the general binding rules

You might need to make changes in order to meet the general binding rules. For example, if you have a non-standard treatment system (such as discharging to a borehole) you might need to change the system you use.

Only apply for a permit if you cannot meet the general binding rules. You will not be given a permit if you could meet the general binding rules.

5. Your property has a cesspool

If you have a cesspool then the 鈥榞eneral binding rules鈥� do not apply.

You must maintain your cesspool and make sure it:

You do not need a permit unless the Environment Agency tells you that you do.

If your system releases sewage into the ground or surface water then it is not a cesspool. If you are not sure what your system is, ask a local installation or maintenance company.

The Environment Agency or your local council can make you repair or replace your cesspool if it鈥檚 in poor condition.

You are breaking the law if your cesspool causes pollution.

If you install a new cesspool

You must:

6. Apply for a permit

Only apply for a permit after you have checked:

  • your sewage system is not already connected to the mains sewer (the 鈥榩ublic foul sewer鈥�)
  • it is not 鈥榬easonable鈥� to connect to the public foul sewer
  • your sewage treatment system does not meet the 鈥榞eneral binding rules鈥�
  • you cannot change your system to meet the general binding rules

The Environment Agency will not give you a permit if they think it is reasonable for you to connect to the public foul sewer or if you could meet the general binding rules by making changes to your system.

You鈥檙e breaking the law if you operate without a permit when you need to have one.

Read the guidance on 鈥楧ischarges to surface water and groundwater鈥� to find out when you do not need a permit.

If you discharge sewage to ground

There are different forms depending on whether you鈥檙e in a groundwater protection zone (SPZ1) or not.

Outside an SPZ1

If your sewage is both:

  • classed as domestic
  • a discharge of between 2 and 15 cubic metres per day

You need to fill in part B6.5 of the environmental permit form.

If your sewage is either:

  • not classed as domestic
  • a discharge of over 15 cubic metres per day

Read the guidance on 鈥楧ischarges to surface water and groundwater鈥� to find out how to apply for a bespoke permit.

Inside an SPZ1

All sewage discharges within an SPZ1 require a permit.

If you discharge less than 2 cubic metres per day, there are different forms for systems that were installed:

If you discharge more than 2 cubic metres per day, there are different forms depending on how much you discharge. If you:

If you discharge sewage to a surface water

If your sewage is both:

  • classed as domestic
  • a discharge between 5 and 20 cubic metres per day

Read the guidance on 鈥楧ischarges to surface water and groundwater鈥� to check if you can apply for a standard rules permit.

If your sewage is either:

  • not classed as domestic
  • not eligible for a standard rules permit

You鈥檒l need another kind of permit. There are different forms depending on how much you discharge. If you:

Before you start

You need:

If you have a commercial property then work out your discharge using British Water鈥檚 Flows and Loads guidance document from the .

Application fee

The fee you pay depends on whether your site is:

  • a domestic household - includes self-catering and holiday let properties, unless you pay business rates on these
  • a charity - either a registered charity or has a HM Revenue and Customs (HMRC) charity number
  • another type of organisation such as a campsite, pub, shop or holiday let that pays business rates

If your site is a domestic household or charity

The application fee to discharge up to and including 5,000 litres (5 cubic metres) per day either to ground or to surface water is 拢125.

If your site is another type of organisation

You鈥檒l pay a different fee depending on whether you鈥檙e discharging to ground or to surface water.

Size of discharge per day Fee for discharging to ground
Up to and including 5,000 litres (5 cubic metres) 拢2,647
Over 5,000 litres (5 cubic metres) and up to and including 15,000 litres (15 cubic metres) 拢4,269
Over 15,000 litres (15 cubic metres) 拢10,062
Size of discharge per day Fee for discharging to surface water
Up to and including 5,000 litres (5 cubic metres) 拢2,434
Over 5,000 litres (5 cubic metres) and up to and including 20,000 litres (20 cubic metres) - for a standard rules permit 拢1,229
Over 5,000 litres (5 cubic metres) and up to and including 50,000 litres (50 cubic metres) 拢6,463

Habitats assessment fee

If you鈥檙e applying for a permit in certain protected sites, the Environment Agency might need to carry out a habitats assessment.

Protected sites include:

  • a European Site within the meaning of the Conservation of Habitats and Species Regulations 2017
  • a site referred to in the National Planning Policy Framework 2023 as requiring the same assessment as a European Site
  • a site of special scientific interest within the meaning of the Wildlife and Countryside Act 1981
  • a marine conservation zone within the meaning of the Marine and Coastal Access Act 2009

The habitats assessment fee is 拢2,035.

You do not need to pay the fee if both of the following apply:

  • your site is a domestic household or charity
  • your site discharges no more than 5,000 litres (5 cubic metres) of domestic sewage per day

Find out how to pay the fee.

Annual fee

There鈥檚 an annual subsistence fee for sites that are not domestic households or charities.

Size of discharge per day Fee
Up and including 5,000 litres (5 cubic metres) 拢247
Over 5,000 litres (5 cubic metres) and up to and including 20,000 litres (20 cubic metres) - with operator self monitoring 拢813
Over 5,000 litres (5 cubic metres) and up to and including 20,000 litres (20 cubic metres) - without operator self monitoring 拢888
Over 20,000 litres (20 cubic metres) and up to and including 50,000 litres (50 cubic metres) - with operator self monitoring 拢1,253
Over 20,000 litres (20 cubic metres) and up to and including 50,000 litres (50 cubic metres) - without operator self monitoring 拢1,592

How long it takes

The Environment Agency will check your application and let you know if you need to send more information.

Once your application is confirmed as complete you should expect it to take at least 4 months to get a decision. The Environment Agency will tell you if your application will take longer.

If your application is refused

If your application is refused, you鈥檒l be told why and how you can appeal.

Complying with your permit

See the guidance on how to comply with your permit, including maintenance, record keeping and pollution reporting requirements.

Get help with your application

If you are sure you need a permit you can ask the Environment Agency for advice before you apply.