Septic tanks: facts and legislation

Septic tanks: facts and legislation

Installation of a drainage tank (septic tank) in a domestic garden. 4000 Litre Capacity.

What is a septic tank?

A septic tank collects wastewater and sewage from a property that is not connected to the main sewer system.

How does it work?

  • Wastewater enters the underground tank from an inlet pipe and gradually separates.
  • Solids settle at the bottom, oils and greases form a layer of scum at the top, and the liquid matter remains in the middle.
  • This clarified wastewater exits via an outlet pipe into a drain field or into a surface watercourse (stream, ditch, river, etc)
  • The remaining scum and solids in the tank are broken down into sludge by naturally occurring bacteria.

What are the rules?

  • The householder is responsible for meeting the Environment Agency’s ‘general binding rules’ of owning a septic tank.
  • These state that the sewage must be domestic in nature, and must not cause pollution.
  • The septic tank must be emptied and checked at least annually by a qualified waste handler and an auditable paper trail kept. Timescales will depend on the variables of each installation.

Septic tank problems

Problems are usually caused by householder misuse, such as:

  • Not keeping the drainage field protected and operational
  • Putting inappropriate items and chemicals into the system (some cleaning products can kill off the natural bacteria, upsetting the eco balance of the system)
  • Not having the tank emptied and checked regularly by a specialist contractor

Changes to the rules

In January 2015, the rules changed so that existing septic tanks which discharge to watercourses must be upgraded to a full sewage treatment plant by 1st January 2020, or before the property is sold if that is before the deadline. Visit the website below for all the details on the latest legislation https://www.gov.uk/guidance/general-binding-rules-small-sewage- discharge-to-the-ground

Looking for more information

For more information on septic tanks, on how to maintain them, how often to you should get them cleaned or emptied visit our advice page, what is a septic tank? download and print off our septic tank tip sheet, or alternatively you can call our team on 0333 344 2937 and we will be happy to help.