Practicalities of private sewage treatment 4:
Rules and Responsibilities
Through this series, SCRT, on behalf of the Love Windermere Partnership Sewage Theme workstream, aims to provide essential information for owners and operators of private sewage treatment systems, including those not connected to the main sewage system, on how they can minimise their environmental impact.
Given that households are responsible for managing their non-mains sewage systems, there are several rules which need to be followed to avoid polluting the environment and ensure compliance with current regulations. The specific rules a household must follow vary depending on the volume of sewage discharged into the environment, which relates to the number and size of properties connected to the treatment plant. If you are in any doubt, guidance and tools for calculating your discharge volume are available online (Sewage discharges: calculator for domestic properties – GOV.UK). 
Small sewage discharges less than 2m3 per day to the ground or 5m3 per day to water are regulated by the General Binding Rules. These rules set out a series of instructions for how you should maintain and operate your treatment system to prevent pollution. You can find detailed guidance for discharges to ground and water. The regulations were updated in 2015 and 2023, so check that you remain compliant. Additional resources to help understand the rules are also available on the Call of Nature website (www.callofnature.info).
Failure to comply with these rules can result in pollution of the local watercourse and may lead to enforcement action by the authorities being taken against you.
For discharges over 5 m3 per day to water or 2 m3 per day to the ground, your sewage system will require a permit from the Environment Agency. The General Binding Rules document outlines the processes and treatment standards you must follow to maintain compliance and prevent pollution, including any specific treatment requirements. If you think your discharge may require a permit, more information is available online (Septic tanks and sewage treatment plants: what you need to do: Apply for a permit – GOV.UK) or by contacting the Environment Agency. The Environment Agency inspects permitted sites to ensure compliance and may be able to offer advice and guidance on meeting your permit conditions. Repeated or major breaches of your permit may result in enforcement action being taken against you.
In some instances, a single sewage system will be shared between multiple properties, particularly in areas with limited space, which can lead to difficulties and/or issues if not appropriately managed. There should be an agreement between properties sharing a sewage system that clearly sets out responsibilities regarding emptying, maintenance, and costs. If the system itself is located outside your property boundary, you may also need additional clauses to ensure access for inspection or emptying. Delegating responsibility can also cause confusion between landlords and tenants. Generally, it is up to the landlord to empty and maintain the sewage system unless specifically written into the rental agreement. If the responsibility does lie with the tenant, the landlord should provide details of when the tank needs emptying, additional maintenance required and may be able to recommend a local licensed waste carrier.
We have developed handy homeowner packs, which you can download here.