A septic tank is a key component of the septic system; a small-scale sewage treatment system common in areas that lack any connection to main sewage systems.

Septic tanks should only be used in conjunction with a form of secondary treatment; for example, a soakaway or drainage field, drainage mound or constructed reed bed wetland.

Septic tanks are compartmentalised tanks that separate solid and liquid waste. The liquid waste is discharged (usually to a soakaway or drainage field), and is then treated naturally by percolation through the soil, whilst the solid waste remaining is stored in the tank until it’s manually emptied – as the tank just retains solids, it doesn’t need to be emptied as often as a cesspool, so you’ll only pay for this to be done a once or twice a year.

Common septic tank problems are:

A cesspit is a sealed, watertight underground tank that captures wastewater and sewage and simply collects it, without processing or treating it at all.

Cesspits, also known as cesspools, act as holding tanks for both liquid and solid waste. They tend to hold around 6-8 weeks of waste (although specialist sizes can increase this capacity), and therefore need to be emptied on a relatively regular basis. Once capacity is reached, the cesspool must be emptied; this will be at a cost of around £100-£300 each time, depending on factors such as location and availability of resources. Cesspits tend to feature vents that allow for the escape of gasses.

Common cesspit problems are:

Domestic sewage treatment plants can be used when mains drainage is inaccessible and provide a modern alternative to septic tank systems. These sewage treatment plants are designed to process waste water, producing a treated effluent suitable for discharge to a drainage field or natural watercourse.

Despite potentially sounding like a heavy-handed option, domestic sewage treatment plants are actually an increasingly affordable and popular off-mains drainage solution. Sewage treatment plants are designed to increase the activity of the naturally-occurring microorganisms that break down waste, to the point where liquid waste can be safely discharged into a watercourse or soakaway. Solid waste still needs to be manually removed, but is vastly reduced in volume compared to septic tanks and cesspits.

Common sewage treatment plant problems are:

A sewage pumping station is a solution for households that do not have direct access to main sewage systems but have them in the vicinity of the property.

Domestic sewage pumping stations are normally designed to handle raw sewage that is transferred directly from a property via underground gravity pipelines. Sewage is fed into and stored in an underground pit, commonly known as a wet well. The well is equipped with electrical instrumentation to detect the level of sewage present. When the sewage level rises to a predetermined point, a pump will be started to lift the sewage upward through a pressurized pipe system called a rising main from where the sewage is discharged into a main sewer system usually within several hundred meters.

Common sewage pumping station problems are:

Drainage fields (also commonly known as soakaways or leach fields) are a form of secondary treatment system used in conjunction with septic tanks or sewage treatment plants.

Soakaways are used to remove contaminants and impurities from the liquid that emerges from a septic system. A drainage field is effective for disposal of organic materials readily catabolized by a form of septic treatment system. The soakaway typically consists of an arrangement of trenches containing perforated pipes and porous material (often gravel) covered by a layer of soil to prevent animals and surface runoff from reaching the wastewater distributed within those trenches.

Drainage fields require a strict design process in accordance with Building Regulations, British Standards and other codes of practice to ensure they are constructed correctly in a suitable location. An incorrectly constructed drainage field will cause environmental pollution as well as efficiency issues.

Common drainage field and soakaway problems are:

Septic systems, septic tanks and sewage treatment plants including drainage field soakaways must be designed and constructed in accordance with Environment Agency Regulations, Building Regulations – Approved Document H, British Water Code of Practice and BS 6297: 2007 + A1 2008.

It is important that advice is taken as to what alternatives are available for individual situations and that basic feasibility studies are carried out prior to any expensive construction work commencing.

Basic feasibility includes:

Septic system installations and repairs usually require planning applications and associated building notices, so it is important that you choose a contractor who is experienced in all aspects of the design and construction process from the beginning.

Most buildings insurance policies provide cover for septic tank problems or damage to other drains and drainage systems under an area within the policy called ‘Accidental damage to underground services’ (or similar).

Accidental damage can be a confusing term, but quite simply it means anything unforeseen that hasn’t been caused on purpose. Problems typically covered are those such as tree root damage, or a collapsed drain caused by vehicle movement. Problems that would not be covered are those such as soft blockages or systems that haven’t been installed correctly.

The definition or interpretation of accidental damage can vary from insurer to insurer, and many claims that we manage involve highly technical discussions. Our team combines technical drainage expertise with claims handling experience, to ensure that we can identify when a possible claim would be valid, and successfully handle all negotiations on your behalf.

The following types of septic tank or drainage system damage are typically covered by buildings insurance policies:

Get in touch with us to discuss your issue and we can give you advice prior to initiating your claim.

Prior to buying or selling a property, it is strongly recommended that a drainage survey is carried out. This is often neglected or poorly carried out for properties with off-mains drainage.

Replacement septic tanks and sewage treatment plants can cost thousands of pounds, so a full and detailed survey of existing systems can be extremely cost effective in the long run. If you are buying a property with a known septic tank or sewage treatment system, you should seek to answer the following questions:

Operators of septic tanks and treatment plants have legal responsibilities which involve BIG fines!

Click here for more information.