In 2015 the EA brought in reforms of regulatory systems regarding the control of small sewage discharges from septic tanks and small sewage treatment plants in England.
The biggest change is that sewage discharged to surface water (stream, river, lake etc) must receive treatment from a sewage treatment plant.
The EA States:
You must use a small sewage treatment plant to treat the sewage if you’re discharging to a surface water such as a river of stream… Discharges from septic tanks directly to a surface water are not allowed under the general binding rules. If you have a septic tank that discharges directly to a surface water you will need to replace or upgrade your treatment system ny 1st January 2020, or when you sell your property if before this date.”
Sewage discharged to ground must either receive treatment from a septic tank and drainage field or from a sewage treatment plant and drainage field or ground infiltration system.
New discharges must not be made to an enclosed lake or pond, and must not be within 30 metres of a public foul sewer.
There is more information in the useful information section of our website, which has documents and links to the Environment Agency website.