13. Septic tank

A septic tank is a large, underground wastewater treatment system commonly used in rural or non-sewered areas to treat and dispose of household sewage and wastewater. It is a vital component of on-site sewage disposal systems and is designed to separate solid matter and floatable materials from the wastewater, allowing the liquid effluent to undergo further treatment as it flows into a drain field or soakaway system.

Here is how a septic tank typically works:

Wastewater collection	All wastewater from toilets, sinks, showers, and other plumbing fixtures in a property is directed into the septic tank.
Separation	Inside the septic tank, solid waste materials settle at the bottom, forming a layer of sludge, while lighter materials like grease and oils float to the top, creating a scum layer. The middle layer consists of relatively clear liquid effluent.
Biological treatment	Bacteria and enzymes present in the tank help break down and digest the organic matter in the sludge and scum layers. This biological treatment partially purifies the wastewater.
Effluent discharge	The liquid effluent, which is now less polluted, exits the septic tank and flows into a drain field or soakaway system through a distribution box or pipes with small holes. This effluent is further treated as it percolates through the soil, where natural processes continue to break down contaminants and filter the water.
Final treatment and disposal	In the drain field or soakaway system, the treated effluent is released into the soil, where it undergoes final purification and ultimately re-enters the groundwater or nearby surface water bodies, such as streams or rivers.

Septic tanks require regular maintenance, including periodic pumping to remove accumulated sludge and scum layers. Proper maintenance ensures the system's efficient and safe operation. Failure to maintain a septic tank can result in backups, overflows, and environmental contamination.

It is essential to follow local regulations and guidelines when installing, using, and maintaining septic tanks, as specific requirements may vary depending on regional environmental and health standards.

Regulations

Compliance with British Standards	When considering septic tank compliance with British Standards, it is essential to understand that standards can evolve over time. Septic tanks installed several years ago might not meet current standards. However, these older systems can still be functional and compliant with the regulations that were in place at the time of installation. If you are concerned about compliance, consider having an inspection by a qualified professional.
Satisfaction of Environment Agency’s General Binding Rules (GBR)	The General Binding Rules (GBR) for septic tanks in England outline specific requirements for systems discharging small volumes of treated wastewater. These rules primarily focus on environmental protection, especially concerning watercourses and groundwater. GBR compliance may involve requirements for using low-impact systems, ensuring proper wastewater treatment, and adhering to discharge limits. Checking compliance may involve reviewing your system's specifications and ensuring it meets these regulations.
Water flow destination (watercourse or land)	Understanding the flow of treated wastewater is crucial for environmental stewardship. If your septic tank discharges into a watercourse, it is essential that the water meets quality standards to avoid contamination. If the discharge is onto land, the soil must have adequate drainage capacity to prevent waterlogging. Soil testing can determine suitability.
Overflow or soakaway system presence	An overflow or soakaway system provides an extra layer of protection for your septic tank. It is designed to handle excess wastewater in emergencies. This system helps prevent flooding of the drain field or soakaway area. Ensuring that it functions correctly is vital to avoid overflows during heavy usage or rainfall.
Location within property boundaries	The location of your septic tank components within your property's boundaries can impact ownership, maintenance, and potential disputes with neighbours. If any part extends beyond your boundaries, you might need legal agreements or easements to access and maintain these components.
Consents from regulatory bodies	Regulatory consents are essential for legally operating septic tank systems. In the UK, the Environment Agency (EA) or local environmental authorities typically issue these consents. To obtain them, you will need to demonstrate that your system complies with environmental and safety standards. This may involve submitting detailed plans and conducting soil tests.
Enforcement actions and pending actions	Enforcement actions can arise if your septic tank system is found to be in non-compliance with regulations. Past enforcement actions should be disclosed, as they indicate a history of non-compliance. Pending actions can affect your ability to sell the property or use the system. Resolving these actions promptly is essential.
Emptying frequency and cost	Septic tank emptying frequency depends on various factors, including tank size, household size, and usage. Smaller tanks may require more frequent emptying. Costs can vary widely based on location and service provider. Regular maintenance and scheduled emptying are crucial to prevent system failure.

Other considerations

System condition and blockages	Monitoring the condition of your septic tank system is essential for its longevity. Regular inspections by professionals can help identify issues early. Blockages can result from improper use or system problems. Resolving blockages promptly is vital to prevent damage and ensure proper operation.
Neighbour complaints and disputes	Neighbour complaints often revolve around odours, overflows, or perceived environmental impact. Addressing these concerns proactively can prevent disputes. Maintaining open communication and potentially installing odour control measures can mitigate issues.
Maintenance and repair agreements	Agreements covering maintenance and repair responsibilities are essential when multiple properties share a septic system. These agreements specify who is responsible for costs and upkeep. It is crucial to have these agreements in writing and legally binding.
Sharing costs and disputes	Sharing costs for septic system repair or maintenance should be clear and agreed upon. Disputes can arise when one party feels unfairly burdened. Legal agreements can help resolve these issues, and mediation may be necessary in some cases.