General binding rules explained

Properties in rural areas not connected to mains drainage typically rely on private systems like septic tanks or small sewage treatment plants. Changes to regulations governing discharges from these systems often come to light during property sales, when drainage investigations occur. It’s crucial for property owners and buyers to understand these rules.

The law, governed by the Environmental Permitting (England and Wales) Regulations 2016 (EP Regulations 2016), regulates discharges to groundwater and surface waters. Small sewage discharges (SSDs) in England fall under different regulations.

An environmental permit may be required unless exempted. A SSD of domestic sewage is exempt from the requirement to have an environmental permit, provided it meets a number of conditions including:

  • A general condition that it does not cause pollution of groundwater or surface water.
  • Volume threshold conditions which differ for discharges to surface and groundwater.
  • The discharge meets the location conditions in relation to sensitive and protected sites.

In order to benefit from the exemption, SSDs must not contain any trade effluent, but can include discharges from some small businesses, for example: small hotels, pubs, restaurants, and offices.

When purchasing a residential property served by a septic tank or sewage treatment plant, it’s crucial to inquire about whether the system qualifies for an exemption from regulations. Sellers are obligated to provide the new owner with written notice detailing the ongoing sewage discharge and maintenance requirements of the system. If the system is old (or there is no paperwork available) then the buyer should consider having a survey done to make sure it complies with the general binding rules.

According to general binding rules, when properties with septic tanks discharging directly into surface water are sold, the responsibility for upgrading or replacing the existing system must be negotiated between the buyer and seller as a condition of sale. This is because such discharge does not meet exemption conditions and can only continue with an existing environmental permit.

Responsibility for compliance lies with the “operator” of the sewage system, defined as the person controlling its operation. Identifying the operator can be complex, as it may include users on neighbouring land or tenants agreeing to maintenance responsibilities.

Owners and estate managers should ensure systems are evaluated by a surveyor to confirm their eligibility for exemption, including discharge volume and maintenance checks. If a septic tank or sewage treatment plant fails to meet EP Regulations 2016 standards or does not qualify for an exemption, upgrading or replacement is necessary, otherwise, an environmental permit is required. While general binding rules may not be widely known, they are legally binding, so it’s essential to be aware of them to avoid complications.

Things To Remember

If you are looking for a new house, and the property contains a septic tank or sewage treatment you must consider its current condition, how long ago it was installed, the cost to run and maintain it, if it is shared and whether it complies with the general binding rules.

General binding rules: small sewage discharge to the ground – GOV.UK (

This article is intended for guidance only and does not constitute legal advice – 2024


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Caroline Polder
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