Environmental guidance for your business in Northern Ireland & Scotland

Septic tanks

If a your domestic property has no connection to a foul sewer, and no connection is possible, you will most likely have a septic tank to deal with sewage and waste water from your premises.

This might be a septic tank that deals only with the waste water from your house, or it might be a septic tank that deals with waste water from a number of neighbouring properties.

Septic tanks use natural biological processes to break down sewage and waste water and produce a discharge that can be made safe and harmless when slowly added to well aerated soil, or by another final treatment.

If the natural processes are stopped, then problems can occur. Non-mains sewerage systems can pollute groundwater (all water lying below the water table or in aquifers) if they are poorly located, built or operated. This can affect water supplies, such as drinking water or water for livestock. It can also pollute surface water in rivers, streams and lochs/loughs.

This guide explains what you should do to look after a septic tank and how to prevent problems arising. It also tells you how to register existing or new septic tanks.

If you are a plumber or builder installing a septic tank there are certain things you must do before installing a tank. This guideline outlines these responsibilities and the authorisation you need before you start work.

NOTE: In England there are new rules that apply to new septic tanks that discharge directly to water (e.g. a river or stream) . These new rules do not apply in Scotland or Northern Ireland.

COVID-19 Information: Startup information for packaged wastewater treatment plants after the shut down period

Following the actions that the UK government established in March 2020 to help to reduce the transmission of coronavirus in our communities, certain businesses and venues have been required by law to stay closed to the public for a prolonged period.

For businesses who use off-mains wastewater treatment, such as package treatment plants, there are a number of recommended actions that should be taken in order to:

  • protect your equipment,
  • enable a smooth start-up, and
  • minimise the risk of pollution when restarting your plant

A list of these actions can be found in the British Water guidance document - Startup information for packaged wastewater treatment plants after shut down period.(Adobe PDF - 177KB).

Additional resources

Environmental News Blog

NetRegs on NetRegs on youTube

View our latest videos & subscribe to our channel.

NetRegs Update Newsletter

Free monthly email newsletter with environmental updates for Northern Ireland and Scotland

Sign up for free today!


NIEA - Apply online

SEPA - Application forms