The Environment Agency (EA) has introduced new rules regarding the discharge of treated sewage by systems installed and in use on or after 01 January 2015.

If you have a septic tank you need to identify whether it discharges to a river or stream (surface water discharge) or whether it discharges to a drainage field, as after 01 January 2020 discharges to surface water from both old and new septic tanks will no longer be permitted by the EA.

If you have a septic tank that discharges directly to surface water you will need to replace or upgrade your treatment system by 01 January 2020.

Where properties (domestic or commercial) with septic tanks that discharge directly to surface water are sold before 01 January 2020, responsibility for the replacement or upgrade of the existing treatment system should be addressed between the buyer and seller as a condition of sale.

It is not uncommon for a septic tank or soakaway to be located on neighbouring land. In these instances, the responsibility to upgrade still lies with the owner of the septic tank whether the soakaway is on their land or not, so it is important to act quickly. The process could be slowed and deadline potentially missed if issues occur during the upgrading process.


If your system requires replacing or upgrading due to its discharge location, you have three possible options:

• connect to mains sewer

• install a drainage field so the septic tank can discharge to ground instead

• replace your septic tank with a small sewage treatment plant.

Only small sewage treatment plants can be permitted to discharge to a surface water such as a river or stream. A small sewage treatment plant (also known as a package treatment plant) treats the liquid so it's clean enough to go into a river or stream.

It is possible to apply for a permit for discharge to surface water from a septic tank, however these are only granted in exceptional circumstances. It is advisable to contact the EA before applying.

Discharging to ground:

Discharge from septic tanks and sewage treatment system can be made to ground via drainage fields.

Discharge to a soakaway borehole can only be made from a sewage treatment system and must be permitted by the EA. Permits must be applied for in the following circumstances:

if you discharge:

• to a well, borehole or other deep structure

• more than 2 cubic metres (2,000 litres) per day

If any part of the building your system serves is within 30 metres of a public sewer, the EA will not allow you to start a new discharge. If there is a good reason why you cannot connect to the sewer (eg. a river or a hill in the way) then you must apply for a permit from the EA.