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Information On Septic Tanks and the General Binding Rules

How Septic Tank Works

A septic tank often gets confused with a Cess pit, however they act differently. A septic tank is an underwater sedimentation tank that uses biological decomposition followed by distribution to a drainagefeild. The tanks are very simple and normally have two chambers both with T pipes to prevent scum from leaving the tank.

How It Works

  1.  Water from your kitchen, bathroom etc runs through one main drainage pipe leading to your septic tank.
  2. Underground the septic tank starts the process of holding the wastewater. It needs to hold this long enough, so the solids     settle down to the bottom, while oil and grease floats to the top.
  3. After this process the liquid wastewater (effluent) will then be able to exit the tank into the drain field. 
  4. This wastewater is discharged through pipes onto porous surfaces. These allow wastewater to filter though the soil. 
  5. The soil accepts, treats, and disperses wastewater as it percolates through the soil, discharging to groundwater.
  6. Finally, the wastewater percolates into the soil, naturally removing harmful coliform bacteria, viruses and nutrients. 

Cess Pits

Cesspools / cesspits work? Your cesspit is a sealed, watertight underground tanks that capture wastewater and sewage and simply collect it, without processing or treating it in any way. ... Cesspits will usually be discreetly buried underground with a single manhole cover for access by the waste collection team

External web link - General Binding Rules

If you own, live in, or are building a property off the mains sewage network it’s important you’re aware of changing legislation around septic tanks. In a bid to tackle water pollution, the Environment Agency has set out General Binding Rules, which mean you have until 1 January 2020 to replace or upgrade your system.

What are the 2020 General Binding Rules?

The general binding rules for small sewage discharges (SSDs) have been put in place to protect England’s surface water resources (e.g. rivers, streams etc.) from pollution caused by septic tanks and other small-scale sewage treatment plants.  

Under the new regulations, you can no longer discharge low quality effluent from septic tanks directly into ditches, streams or other watercourses. Instead, you have the option of replacing your system or upgrading it to incorporate a drainage field. This is also known as an infiltration system and means the effluent can seep into the ground instead for further treatment by soil bacteria.

Do the new rules apply to me?

If you’re recognised as an ‘operator’ of a septic tank then the answer is yes! Under the General Binding Rules, an ‘operator’ can be: 

  1. The owner of the system,
  2. Someone who uses the septic tank,
  3. Another person (e.g. a tenant of leaseholder) who agrees to be responsible for the operation and maintenance of the system, through a written agreement with the owner of the system.

What are my options?

If your current system is recognised as causing surface water pollution, then you have three options:

  1. Connect to a mains sewer - if one is close enough,
  2. Install a drainage field - only viable if you have enough suitable land,
  3. Replace your septic tank with a more efficient, modern sewage treatment plant

The most common outcome will be to replace your tank. More modern and effective sewage treatment systems are available today, which produce a much higher-quality effluent. They work by encouraging the formation of bacteria, which then breaks down and digests raw sewage. The result is cleaner, odourless water that can be safely released into groundwater reserves.

Sequence batch reactor (SBR) systems are a particularly popular option. They minimise the risk of untreated waste overflowing by treating it in batches using a series of chambers and an additional buffer tank. They are the most technologically advanced and durable type of sewage treatment system – and here at Graf UK, we see them as the future of off-mains wastewater treatment. SBR systems, such as our One2Clean range, treat waste by mixing and circulating effluent inside one main tank. Because the incoming flow rate has no impact on the speed of the treatment process, they deliver an overall more consistent, efficient performance, along with the highest discharge quality.

Whichever system you choose, yearly checks are recommended to ensure ongoing optimum performance is maintained. Some manufacturers, including GRAF UK, offer maintenance contracts as well as installation services – so make sure you have a plan in place to ensure complete peace of mind.

What else do I need to know? 

Under the new General Binding Rules, your septic tank or treatment plant must meet British Standards BS EN 12566 (if in any doubt at all, ask your manufacturer). In addition, the drainage field must meet BS EN 6297:2007 standards.

You also need to ensure that your system is sized and installed correctly, in accordance with British Water’s Flows and Loads 4 guidance. Volumes must be recalculated if the amount of sewage going into the septic tank increases – for example after an extension or if connecting to a new sewage source. Furthermore, you will need to make sure your tank is regularly emptied and maintained by a professional (e.g. a registered waste carrier) in line with the manufacturer’s instructions.

If you are selling or buying, the seller is now legally required to inform potential buyers in writing if a property has a septic tank – including details of its precise location and maintenance requirements.

Bear in mind that if you live in Wales, Scotland, or near a groundwater source protection zone (SPZ1), different rules may apply. Your manufacturer will be able to provide guidance, but always check with your local environmental agency too.

External web link -


A very common problem, as with any other water-body that's underground, is the overflow of water after a period of heavy wet weather. Excess in the inflow of water into these septic tanks will cause the wastewater inside to overflow  and flush into the soakaway causing it to block and then causing the tank to overflow or back up to the toilets.

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ISO 14001 has become the international standard for designing and implementing an environmental management system. The standard is published by ISO (the International Organization for Standardization), an international body that creates and distributes standards that are accepted worldwide. The most recent version of the environmental management system requirements was published in 2015, and is referred to as “ISO 14001:2015.” The standard was agreed upon by a majority of member countries before being released and updated, and as such it has become an internationally recognized standard accepted by a majority of countries around the world.

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