Buying or selling a house with a septic tank - what you need to know

If you are planning to buy or sell a property with a septic tank then you need to be aware of the relevant regulations. It is important that all parties understand the applicable law if transactions are to proceed smoothly and quickly.

A septic tank is an underground water-tight container which collects sewage and waste water from a property where the property is not connected to a mains sewer system. This type of system is very common in rural properties and a well-maintained system is unlikely to present any issues.

New Regulations for septic tanks?

Some of the commentary on this topic refers to new rules or regulations having been introduced in 2020 but this is slightly misleading as we explain more fully below. The current law is found in the Environmental Permitting (England and Wales) Regulations 2016 (“the Regulations”) which consolidate earlier regulations. The Regulations refer to 21 rules which are known as the General Binding Rules (“the GBR”).

The General Binding Rules

The GBR specify the conditions that septic tanks must meet in order to be used without an environmental permit. The rules are contained in a policy paper but they are legally binding because the Regulations state that exempt discharges (i.e. those that do not require a permit) must comply with the GBR.

Most of the rules apply to all small sewage discharges but some of the rules only apply to discharges that started, or changed, on or after 1 January 2015 (referred as ‘New Discharges’).

The GBR place obligations on the ‘operator’ meaning the person who has control over the operation of the septic tank. Note that this could be the owner of the septic tank, someone who uses it (e.g. a neighbouring landowner) or another person who has agreed to be responsible for the maintenance of the system in a written agreement (e.g. a tenant).

Key Points from the GBR

The discharge must not cause pollution of surface water or ground water.
You can discharge up to 2 cubic metres per day to the ground (e.g. a soakaway in the garden) using either a septic tank or small sewage treatment plant. The Environment Agency has published a helpful calculator for householders to work out the daily discharge.
You cannot use a septic tank to discharge to surface water (e.g. a river or stream). You need small sewage treatment plant to do this (and can then discharge up to 5 cubic metres per day).
The system must comply with the relevant British Standard that was in force at the time of the installation and must be operated in accordance with the manufacturer’s specification. Maintenance must be undertaken by someone who is competent and waste sludge must be safely disposed of by an authorised person.
New Discharges:
- require both planning permission and building regulations approval for the system;
- are not permitted if any part of the building that the system serves is located within 30 metres of a public sewer or if the discharge could reasonably be made to the foul sewer; and
- will require a permit if the discharge is in or close to designated sensitive areas.

Selling a house with a septic tank

The GBR were last updated on 21 January 2015. However, the Environment Agency publishes guidance on how to comply with the GBR and this is updated more frequently. In 2018, this guidance was amended to include the following statement:

“Where properties with septic tanks that discharge directly to surface water are sold before 1 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”.

However, the guidance was further amended on 21 January 2019 and this statement was removed. The guidance now simply states that if you have a septic tank that discharges directly to a watercourse you need to take action as soon as possible to make sure you meet requirements.

If you currently have a septic tank that discharges to surface water then you should address this now and will certainly have to deal with this issue upon any proposed sale. A purchaser may require upgrade works to be completed prior to completion or may seek a price reduction if the purchaser is to undertake the works after completion. This matter should be addressed at an early stage in the conveyancing process so that appropriate wording can be added to the contract if required.

When a property is sold, the operator must give the purchaser a written notice stating that a small sewage discharge is being carried out and must provide a description of the waste water system and its maintenance requirements. However, septic tanks do not need to be registered and there is no legal requirement to keep records of maintenance (although this is strongly recommended as purchasers will enquire about maintenance).

Buying a house with a septic tank

The solicitor acting for the buyer should raise specific enquiries relating to the septic tank. For example: where is it located, when was it installed, is use shared with any other properties, when was it last serviced, can the seller provide copies of any planning permission, building regulations approval, warranties or indemnities relating to the septic tank?

Buyers should satisfy themselves that any system is in good working order and does not cause pollution. There could be costs involved in engaging a surveyor to inspect the system and ongoing maintenance inspections. There may be further costs if a septic tank needs to be upgraded or replaced and this is something that may need to be negotiated with the seller. It is also particularly important to check that the appropriate rights and obligations are in place if the system is located on someone else’s property.

What you need to do

Property owners should be aware of the GBR and should consider whether their septic tank complies. You can get advice from a competent service engineer if you need help understanding what treatment system you currently have. British Water provides a list of accredited service engineers. There may be other competent service engineers.

If a small sewage discharge is not meeting the General Binding Rules the the Environment Agency will usually try to provide advice and guidance to help resolve the issue. However, if this is not successful then enforcement action may be taken and potentially prosecution.

This note only applies to properties located in England as different requirements apply to properties located in Wales.

Please do not hesitate to contact William Marriott or another member of the private property team for specific advice. This briefing note is not a substitute for legal advice on the specific circumstances of the case.