Bishop & Sewell

While not usually an issue for central London properties, for those buying outside the M25 it may be a surprise to find the property you are buying has a septic tank or sewage treatment plant. Certain discharges to groundwater or to surface water require an Environmental Permit (EP) and new rules may apply once a property changes ownership.

Septic tanks and sewage plants should not be confused with a cesspool or cesspit which is a sealed tank that collects the sewage. Cesspools do not require an environmental permit, but must be maintained and emptied by a registered waste carrier.


If you are buying a residential property you should consider whether it is served by a septic tank or sewage package treatment plant, and whether the system in place for the discharge waters qualifies for an exemption under the EP regime.

It is no long a requirement to register an exempt small sewage discharge in England and other regulatory burdens have been reduced. You need not keep maintenance records for five years. While the offence of failing to keep records is removed, the Environment Agency (EA) recommends that records are retained as a matter of good practice. There is also no need to notify the EA if the small sewage discharges ceases.

The exemption registration scheme has been replaced by two sets of general binding rules: one for all existing small domestic sewage discharges and an additional set for new small domestic sewage discharges.


Small domestic sewage discharges that started:

  • Before 1 January 2015 are existing discharges
  • On or after 1 January 2015 are new discharges.
  • In addition, some requirements in the general binding rules for England differ according to whether the discharge is new or existing. Key additional requirements for new discharges include:
  • New small domestic sewage discharges in or near sensitive areas require an environmental permit. Most existing small domestic sewage discharges in or near designated sensitive areas will not require an environmental permit, but the EA may review them and require an environmental permit.
  • Ensuring all necessary planning and building control approvals are in place.
  • Minimum distances from sensitive areas
  • Limitations on the type of surface water that can be discharged to.
  • A small sewage discharge of domestic sewage may be exempt, provided it meets the relevant criteria:
  • General condition that it does not cause pollution of groundwater or surface water
  • Volume threshold conditions.
  • Requirement that the discharge could not be made to the public sewer.
  • Location conditions in relation to sensitive and protected sites and groundwater aquifers
  • Design, construction, maintenance and decommissioning requirements


Anyone considering buying a property with a septic tank or sewage package treatment plant should satisfy themselves that:

  • They have full details from the seller of the details and description of the sewage treatment plant or septic tank
  • It is in working order.
  • It has sufficient capacity to serve the number of intended occupants of the property.
  • It does not cause pollution.
  • It complies with any relevant planning legislation or building regulations.
  • They have full details of the maintenance requirements
  • If either the septic tank or sewage plant or the soak away are on adjoining land:
    • The property has an easement to use the system or soakaway
    • It has a written maintenance agreement where the tank or plant is managed jointly with another landowner or by a third party.
  • If the system also serves other properties
    • That the capacity is sufficient for all properties
    • That there are agreements in place to require other parties to contribute to the costs of the upkeep and maintenance and potential replacement of the system
  • It has been upgraded. The Environment Agency guidance indicates that septic tanks that discharge to surface waters must be replaced or upgraded by 1 January 2020, or on an earlier sale of the property.


  • Whether the system needs upgrading or replacing if it does not meet the current required standards
  • In engaging a surveyor to inspect the system to confirm if it meets the required standards or exemption and advice on any ongoing maintenance requirements
  • The costs of future inspections.
  • Whether an application for an environmental permit is required
  • If there are any adopted sewers in the area that the property could be required to connect to

If you require further advice on any of the issues raised in this article, or thinking of buying or selling a property, please contact Julienne directly or another member of our expert Property team on or call 020 7631 4141.

The above article is largely based on “Regulation of small sewage discharges from domestic septic tanks”, Practical Law Environment and Practical Law Property

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