Small scale sewage discharges (e.g. septic tanks or package treatment plants)

Septic tanks and package sewage treatment works are widely used for the collection and treatment of household wastewater where connection to the mains wastewater treatment system is unavailable.

Septic tanks or package sewage treatment works are a form of wastewater disposal and are often the most appropriate form of treatment in rural areas.

Why do small scale sewage discharges have to be regulated?

Where they are properly maintained, individual small scale sewage discharges rarely present a hazard: however, cumulatively, they can potentially have adverse effects on human health, drinking water supplies, shellfish and bathing waters.

 Small scale sewage dischargesare regulated by the Water Environment (Controlled Activities) (Scotland) Regulations 2011 – commonly known as CAR – and their amendments. Our introduction to the regulations summarises their main features.

Do the regulations apply to me?

If you have a small scale sewage discharges (e.g. septic tanks or package treatment plants) on your property, you must ensure that a registration has been made and it is registered with us.

Proof of registration is required when new properties are being built or existing properties change hands.

Property owners selling existing properties may find that they already have documentation demonstrating that their tank was registered under older environmental legislation – this documentation is acceptable proof, so no further action is needed.

However, if no evidence of a previous registration can be found, you must contact us.

Our CAR practical guide offers further guidance.

What do I need to do?

New discharges

You can apply online for new sewage discharges from septic tanks (or equivalent) to soakaway or watercourse, from a population equivalent (p.e.) of 15 or less.

For new discharges to watercourse or lochs, you are strongly advised to contact us to discuss treatment options before submitting your application.

For new discharges to full soakaway, you will ordinarily be asked to provide the relevant building warrant application number. For a partial soakaway, a building warrant is not applicable.

Existing discharges

Existing discharges previously regulated by a consent issued under the Control of Pollution Act 1974 (CoPA) are considered to be authorised – if you hold CoPA consent, you do not need to apply again under CAR.

To check if your discharge has CoPA consent, please contact us [form1] to request a search of our records. If this check is not carried out prior to applying and it is discovered that a duplicate application has been made, no refund of the application fee will be offered.

If the discharge does not have CoPA consent, then an application under CAR should be made.

You can also apply online for existing sewage discharges from septic tanks (or equivalent) in operation prior to 1 April 2006, to soakaway or watercourses from a population equivalent of 50 or less.

How much will it cost?

The cost of registering a septic tank or small sewage treatment works is £111 by post, or £82 for online applications.

This is a one-off cost with no ongoing fees.

Apply online or by post

You can apply online for a registration.

If you are new to our online system, follow the link to register. If you are already registered, please enter your login details (scroll down to bottom of page).

When prompted by the system to enter a registration type, select ‘point source discharge’ from the drop down menu.

Alternatively, you can download and complete an application form and return it, with the appropriate fee, by post to your local SEPA office (addresses are listed on the application form).

 We have 30 days to determine your application and will notify you of the outcome by post.

Compliance with regulations

Operators are expected to uphold the conditions of their registration or licence and we have powers to withdraw your authorisation if you fail to meet its conditions.

Even after an authorisation has been granted, we can, if necessary, move activities between registration and licences, or from GBR to registration or licences in order to protect the water environment.

If you do not agree with the conditions and requirements imposed by a CAR authorisation or notice, you can make an appeal directly to the Scottish Government. The submission of an appeal does not suspend the operations of all authorisations or notices and its conditions.

Online Registration terminology

Environmental Service: Means the carrying out, operation or maintenance of any activity which is, in the view of SEPA, solely for the benefit of the environment, not being for commercial purposes or in implementation of a statutory duty.
Further guidance on what activities SEPA consider qualify for Environmental Service is available in Annex 1 of guidance to the charging scheme.
Percolation Value (Vp): The percolation value indicates the rate of drainage through the soil in seconds and is used as a measure of the suitability of land for soakaway. A low Vp value indicates good suitability, whereas a high Vp value (usually greater then 140 s) means the land is generally not suited to soakaway.
Population Equivalent (p.e.):

The unit of measure used to describe the size of a waste water discharge. For domestic housing, a minimum of 5 p.e. is used for any house with up to and including three bedrooms. For houses with more than three bedrooms, add 1 p.e. for each additional bedroom. This means that the minimum of 5 p.e. applies for any house with 3 bedrooms or less, regardless of how many people may actually be living in the house.

For non-domestic sewage effluent, population equivalent is calculated by multiplying the number of people using the system by the BOD load (g per person per day) for the relevant discharge type and dividing by 60 (60 g is the average BOD load for one person in one day).

Full details on how to calculate p.e., along with information on BOD loading, are in the Code of Practice document Flows and Loads – latest version available on the British Water website.

Treatment System: Any discharge that is treated is considered to use a treatment system. This treatment system can be a single component, for example a septic tank, or a combination of components, such as septic tank plus reed bed. You must declare all of the treatment system components on the form.

Help, advice and more information

If you require any further help or advice at any stage during the application process, please contact us.