New Regulations for Septic Tank Discharges

If you have a septic tank or small sewage treatment plant which discharges effluent into the ground, then you need to take care, as there are strict rules in place to guard against environmental pollution.

New regulations, known as General Binding Rules, recently came into force as well.  Gilson Environmental Services are specialists in sewage treatment plant servicing and septic tank treatment in Ipswich and the surrounding area. We have compiled this guide to the changes affecting homeowners and businesses.


The New Rules

The Environment Agency’s new General Binding Rules mean that your septic tank is not allowed to discharge directly into a surface water source such as a ditch, stream or river. If it does, you must either upgrade or replace your septic tank treatment system to a full sewage treatment plant by January 1, 2020.

New sewage treatment plants are required to have full BS EN 12566-3 Certification. Alternatively, the discharge to the watercourse must be stopped and diverted to a drainage field. This must be designed and built to the current British Standard BS6297 2007.


Meeting the Standards

Your septic tank must meet the British Standard which applied when it was installed. For new tanks, this is BS EN 12566-1, and for drainage fields it is BS 6297:2007.

However, your tank will still comply with the regulations if it is CE marked, has an appropriate British Standard Certificate, and it is on British Water’s list of approved equipment.

Pre-1983 tanks are exempt from these requirements, as there were no British Standards in place before this date.


Size and Installation

Your septic tank must be big enough for what you want to use it for – check with your installer first. If it is connected to another sewage source then you are likely to need a larger tank and drainage field, or to a new sewage treatment plant instead.

If your new system discharges more than 2 cubic metres (equivalent to 2,000 litres, or 13 people) a day into the ground, you must apply to the Environment Agency for a permit. A septic tank installation will not usually be permitted for more than 15 people under EPP2 regulations.


Emptying and Maintenance

Any settled sludge in the tank must be removed before its maximum capacity is reached. This is because it will affect the tank’s ability to settle solids. So your tank needs to be emptied once a year, or, in the case of larger tanks, in accordance with the manufacturer’s instructions.

The company which carries this out must be registered as a waste carrier, and their tanker drivers should carry a certificate to confirm this. Ask to see it – it’s your responsibility.

Tanks should be repaired or replaced if they have any cracks or leaks in either the pipes or the walls. Faulty mortar joints and missing dip pipes should also be put right, as well as pipe blockages – either going into or coming out of the tank. Any odours from the tank or drainage area should also be investigated.

Electrical equipment can also fail, so you need to ensure any motors are functioning correctly.

Drainage fields can have their own issues. Be wary of septic tanks and manholes ‘backing up’ soggy areas of ground near the field, and pooling water close to the tank or soakaway.

Gilson Environmental Services can help with all your septic tank and sewage treatment plant installation and servicing.


Decommissioning Your Septic Tank

If you stop using the tank or treatment system, all the sludge inside must be removed to guard against any pollution. The tank should also be infilled with rubble, stone or other non-degradable materials.

This only applies if the situation is permanent, and not because the property is temporarily empty. If you are unsure about what to do, ask a maintenance company for advice.


Selling Your Property

If you sell your property, you have a legal responsibility to tell the new owner about any septic tanks or sewage treatment systems. This should include a full description, including any alterations which have been made, its location, and a service history going back for at least seven years.

You should also tell the buyer, in writing, that they are responsible for the septic tank discharge.


Rules for Groundwater Source Protection Zones

A groundwater SPZ1 is the area around a commercial water supply. You can check if your septic tank or treatment system is in one of those on the Government’s official website ( or by asking the Environment Agency.

All areas within 50 metres of a private water supply, such as a spring, well or borehole, are also SPZ1s. In this case, you may have to check with your neighbours.

Owners of existing or new tanks and treatment systems within an SPZ1 must apply to the Environment Agency for a permit. It currently costs £125 to make an application. This may be refused because of the pollution risks involved, or only be granted with conditions attached. The Agency regularly checks that you are complying with the terms of your licence, and has the power to review or revoke it.


New Discharges After 2015

The term ‘new discharges’ refers to any discharges from septic tanks on or after 1 January 2015. It also applies to any new drainage fields installed more than 10metres away from an existing one on or after this date, where the discharge is to ground.

In both these cases, additional regulations apply. You are not permitted to install a new drainage field if it is within 30 metres of a public sewer – your system must be connected to it. If you are building a development with more than one property, then this distance is proportionally increased. For instance, if there are four homes, then the distance is 120 metres (4 x 30 metres).  

You are advised to check with your local water company about sewer access points. If connecting to the mains sewer is not practical, then apply to the Environment Agency for permission to install a small sewage treatment plant instead.

Permits will also be required if the new discharge is inside, or less than 50 metres away from, Special Conservation Areas, Special Protection Areas, Sites of Special Scientific Interest, Ancient Woodland and Ramsar sites (wetlands of international importance).

New discharges also require planning permission or building regulations approval from your local authority. Gilson has a good relationship with the Environment Agency, councils and other local authorities, so we can help you with all this.

And in October 2023, the Environment Agency announced two more updates to the General Binding Rules, covering small sewage discharges.

For more details on these changes, check out our latest blog here.


Septic Tank Treatment in Ipswich from Gilson Environmental Services

As well as offering sewage treatment plant and septic tank installation, we also maintain them, ensuring that they run smoothly for many years.  If you would like to know more about our services, follow this link or call us on 01473 741530.

Gilson Environmental Services are fully independent, so we have no ties to individual manufacturers. This means we can come up with the ideal solution for your home or business. All our work is in line with all the latest regulations.