Many rural and edge-of-village homes are not connected to the mains sewer. Moving into one means inheriting a septic tank or small sewage treatment plant, along with legal responsibilities that a first-time owner may not expect. This article explains what GOV.UK says about those responsibilities in England, focusing on what a new owner or tenant should check before and after the move. It applies to England only: GOV.UK states that there are different rules for septic tanks and treatment plants in Northern Ireland, Scotland and Wales.
Who is responsible
GOV.UK says a person is responsible for, and is the “operator” of, a septic tank or sewage treatment plant if they own the property that uses the system, if the property shares the system with others (in which case they are jointly responsible), or if they have an agreement with the owner that they are responsible, for example where a tenancy agreement says so. That last point matters to movers who rent: the tenancy agreement should be read for who looks after the system. GOV.UK also notes that connecting to the mains (public foul) sewer means no permit is needed.
The “general binding rules”
An operator does not need an environmental permit if the system meets the general binding rules. The rules that apply depend on when the discharge started. GOV.UK distinguishes existing discharges that started before 1 January 2015, those that started from 1 January 2015 up to 2 October 2023, and new discharges from 2 October 2023, with additional rules for the later categories. For a discharge to the ground, the rules for all discharges include that:
- no more than 2 cubic metres (2,000 litres) a day is discharged, otherwise the property must connect to the public sewer where reasonable or apply for a permit;
- only domestic sewage is discharged;
- the discharge must not cause pollution of surface water or groundwater;
- a septic tank or small sewage treatment plant must be used with a drainage field, and effluent from a septic tank must not go to a watercourse;
- the discharge must not be in a groundwater source protection zone 1, otherwise a permit is required.
GOV.UK adds that a well or borehole cannot be used to discharge waste water to ground, and that a soakaway designed for rainwater and installed after December 2007 cannot meet the rules. Owners with such arrangements must upgrade to a compliant drainage field or connect to the sewer where reasonable.
What an existing system needs
For a discharge that started before 2 October 2023, GOV.UK says to check whether the system meets the general binding rules. If it does not, the operator must either connect to a public foul sewer if it is reasonable to do so or change the system so that it meets the rules, and must apply for a permit if neither is possible. It also says that if the system did not obtain building regulations approval when it was installed, approval may be needed, and planning permission might be too; for a system installed before 1 January 2015, the local council can advise on planning permission.
Maintenance and emptying
The rules say the treatment system should be regularly maintained in line with the manufacturer’s instructions, and must be repaired or replaced if it is not in good working order. GOV.UK gives examples of faults, including leaks, cracks, blocked pipes, waste water not draining properly with pools around the drainage point, sewage smells, and a failed motor or pump. Sludge must be removed (desludged) before it exceeds maximum capacity, at least once a year or as the manufacturer instructs, and the company used to dispose of the waste sludge must be a registered waste carrier. GOV.UK says the operator can check this by asking the company to confirm it or asking the driver for a copy of the waste carrier certificate.
Buying or selling: the duty to hand over information
Anyone selling a property with a system must tell the new operator in writing that a sewage discharge is in place. GOV.UK lists what to include: a description of the treatment and drainage systems, the location of the main parts and the discharge point, details of any changes, how the system should be maintained together with the maintenance manual if there is one, and maintenance records. A buyer can use that list as a checklist when asking the seller and their solicitor for information. For the wider moving process, the site’s guide to exchange versus completion explains the sale timeline in which those questions are usually raised.
If a system stops being used permanently, the rules say anything that could cause pollution, such as remaining sludge, must be removed. This does not apply if the equipment is unused only temporarily, for example when the property is empty.
Common questions
Do I need a permit if my tank meets the general binding rules? No. GOV.UK says an operator who meets all the general binding rules that apply does not need a permit.
Do these rules apply in Scotland or Wales? No. GOV.UK says there are different rules there and in Northern Ireland.
The bottom line
In England, whoever owns, shares or has agreed to look after a septic tank or small sewage treatment plant is the operator, and must meet the general binding rules or hold a permit. That includes regular maintenance, at least annual desludging by a registered waste carrier, and written information handed to the next operator on sale. Movers buying or renting a home with a private system should ask for the maintenance records and manual before completion, and check who is responsible under the tenancy agreement. This is general information, not legal advice.