Compliance with the new rules on septic tanks is required by 1st January 2020.
Homeowners will need to upgrade their drainage systems in order to avoid fines from the Environment Agency. The rules prohibit the discharge of waste from septic tanks into watercourses due to the detrimental impact it can have on the environment.
You must use a small sewage treatment plant to treat the sewage if you’re discharging to a surface water such as a river or stream. A small sewage treatment plant (also known as a package treatment plant) uses mechanical parts to treat the liquid so it’s clean enough to go into a river or stream.
Rules originally came into force 01 January 2015 applying to new septic tank systems but from January 2020 they will be rolled out to include all systems – old and new.
For further information;
https://www.gov.uk/guidance/general-binding-rules-small-sewage-discharge-to-a-surface-water