The general binding rules for septic tanks have seen several updates, with the last major update back on the 1st January 2015. Now there are new septic tank regulations coming in on the 1st January 2020, so you will need to act soon. We have pulled together information to help you ensure your septic tank is compliant in 2020.

Binding Rules

2015 Regulations

The 2015 regulations were called ‘General binding rules: small sewage discharge to a surface water’. There’s a range of requirements that septic tank owners need to adhere to in order to remain compliant with the law.

Under the 2015 rules that are still in place, it’s possible to discharge separate waste water from your septic tank in two ways. Firstly, the waste water can be discharged to a drainage field or soakaway system. This allows the water to disperse in a safe way without any pollution. Secondly, the waste water can be discharged to a watercourse, which means the water flows through a pipe to a stream or river nearby.

Other rules outlined in the 2015 regulations include ensuring the discharge was at least 50m away from any drinking water source. The systems are not allowed to cause pollution either. Proper maintenance in accordance with the manufacturer’s recommendations is required, as is annual servicing and desludging.

These regulations apply to people who have started a new discharge from a sewage treatment plant on or after January 1 2015. They also apply to anyone wanting to change a discharge to ground to discharge to surface water system or vice versa.

Changes Coming Into Effect on 1 January 2020

What Are the New Changes?

The most significant change to the regulations relates to discharging waste water from septic tanks to watercourses such as rivers and streams. It’s no longer allowed to discharge waste water to watercourses because of concerns about pollution. This water is no longer regarded as clean enough to flow into streams, canals, rivers or ditches.

What this means is that any septic tank treatment system that does discharge directly to surface water has to be replaced or upgraded by 1 January 2020. The same applies if you sell your property before that date.

How Business Can Comply with the New Regulations

There are a couple of options open to you if you have a septic tank that discharges to a watercourse and you need to change that. First of all, you could install a drainage field or soakaway system that’s capable of taking your waste water from the tank to the ground. It would then be dispersed without causing any pollution.

Another alternative is to improve the quality of the water you discharge so that it’s clean enough to enter a watercourse. The way to do this is by replacing your septic tank with a sewage treatment plant because these produce a far cleaner kind of water.

The New Standards for Treatment Equipment

Using the Correct Treatment System

If you’re discharging to any kind of surface water, a small sewage treatment plant is required. This cleans the water using mechanical systems, meaning it can be deemed clean enough to enter streams and rivers. As mentioned previously, discharged from septic tanks to surface water are entirely banned now.

Meeting the Relevant British Standard

All treatment systems must meet the British Standard that was in place when the system was first installed. The two standards that are currently in place are BS EN 12566 for small sewage treatment plants and BS 6297:2007 for drainage fields.

BS EN 12566 for Small Sewage Treatment Plants

For small sewage treatment plants, the relevant British Standard is BS EN 12566. It’s split into 7 parts, which you can read about below.

Part 1

The first part relates to prefabricated septic tanks and their best practices.

Part 2

Information on soil infiltration systems and related building specifications.

Part 3

Packaged and assembled domestic sewage treatment plans and the relevant requisites and testing techniques.

Part 4

The standards relating to septic tanks assembled from fabricated kits.

Part 5

Pre-treated effluent filtration systems and all relevant guidelines relating to them.

Part 6

Requirements, grading and testing practices for prefabricated treatment units for effluent from septic tanks.

Part 7

Requirements, grading and testing practices for prefabricated tertiary treatment units.

BS 6297:2007 for Drainage Fields

BS 6297:2007 is a code of practice that covers the design and installation of drainage fields used in relation to waste water treatment systems. Things like planning, site investigation and the assessment of site characteristics are all covered by this code. It should be consulted when choosing and installing any new drainage fields for your discharge.

Finding Out if Your Treatment Equipment Met the British Standard Upon Installation

If you can find the company that was responsible for installing your treatment equipment, you should be able to check with them that it complies with the relevant British Standard that was in force at the time of its installation.

For equipment that was installed before 1983, no action needs to be taken because British Standards were not in place until that year.

Making Sure the Surface Water Has Flow

Under the new regulations, new discharges are not allowed to reach ditches or surface water that doesn’t flow throughout the year. Where discharges to watercourses are allowed, there has to be flowing water so that the waste water is taken away safely.

It’s not possible to direct new discharges to watercourses that dry up during the summer months. It’s something that’s not permitted under the general binding rules. The same applies to new discharges being directed to standing water such as lakes and ponds.

Installation and Maintenance

Installation Requirements

When installing a new sewage treatment plant, you’ll need to make sure that the capacity fits its requirements. Size requirements are in place to ensure the system that’s installed is able to handle the largest amount of sewage that will need to be treated at a time. All of his information is outlined in this British Water Code of Practice.

The government also states that any system that’s installed has to be installed in line with the specifications set out by the manufacturer of the system. Each piece of treatment equipment comes with a set of technical requirements or an instruction manual. These should be followed carefully and correctly during installation.

Regular Maintenance

The rules pertaining to the maintenance of treatment systems say that sludge must be removed from the system via desludging before it exceeds maximum capacity. The government says that your system should be desludged at least once a year or in line with the instructions provided by the manufacturer. When the sludge is disposed of, it must be done by a registered waste carrier too.

General maintenance should be planned out according to the instructions provided by the manufacturer. If you don’t have access to these instructions, you should consult a local maintenance company that specialises in working with these systems.

Your treatment system has to be repaired or replaced if it’s not in proper working order. Problems such as leaks, cracked tank walls, blocked pipes and failed pumps are not acceptable under government regulations. Once you’re aware of such problems, they have to be fixed swiftly.

What to do if You Sell Your Property

Selling your property means having to inform the person who will be the new owner that there is a sewage discharge in place. It then becomes their responsibility but it’s yours to ensure they know it’s there and have as much relevant information relating to it as possible.

When informing the new owner of the property of the sewage discharge that’s in place, you must offer a complete description of the treatment plant and drainage system. All of the location information relating to the main parts of the treatment plant, discharge point and drainage systems have to be provided. You should also let the new owner know about any changes that have been made to it and how it should be maintained going forward.

Ensuring the Treatment System is Properly Decommissioned

If you have a septic tank or sewage treatment plant in place but it’s no longer in use, you need to make sure that it’s properly and safely decommissioned. The first step in this process involves removing anything that might cause pollution, such as remaining sludge.

Any electrical devices that remain in place should be removed and disposed of in a safe and proper way. Once everything has been removed, the tank can be filled in with sand or something similar before being sealed. Grass cover can then be established on the ground.

None of this needs to happen if you only stop using the equipment temporarily. But if you want to stop using it permanently, decommissioning it is vital.

Special Requirements

Necessary Permits

In some instances, you’ll need to get permits. This applies if your discharge point is in or close to a designated sensitive area. For example, if you’re within 500 metres of special areas of conservation, special protection areas, protected shellfish water, designation bathing water, Ramsar sites or biological sites of special scientific interest.

It’ll also be necessary to obtain a permit if your new discharge is within 200 metres of an aquatic nature reserve or 50 metres of a chalk river or aquatic local wildlife site. To find out whether any of this applies to you and your septic tank, you can ask the Environment Agency.

The Importance of the Installation Date

If you had your septic tank installed and it began discharging on or after 1 January 2015, it has to comply with the General Binding Rules. This is done by discharging to a drain field. As this is a new discharge, no action will need to be taken.

However, if your system was discharging water before the 2015 regulations came into place, you’ve got what’s known as an existing discharge. Existing discharges are no longer allowed because it pollutes watercourses, as mentioned above. They have to be made compliant before 1 January 2020.


By 1 January 2020, it’ll no longer be possible for septic tanks to discharge water directly to surface water such as rivers, canals and streams. If you have a septic tank that discharges via a drainage field into the ground, the new regulations won’t impact you.

Nevertheless, you should remain aware of all the regulations that are in place and how to comply with them. All of the relevant standards for treatment equipment must be met and failure to comply with current and income regulations could result in fines.



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