Septic Tanks Guide: How Do They Work?

septic tanks and how do they work

Perhaps you have bought a home or business premises that is fitted with a septic tank? Or maybe you need to consider having this alternative drainage system set up?

Whatever your circumstances, understanding how septic tanks work will help you recognise problems when they arise and address essential maintenance needs. In this handy septic tank guide, we answer your questions concerning how septic tanks work, how septic systems work, how to maintain and empty them, and what the difference is between a septic tank and cesspit.

How does a septic tank work?

Septic tank systems are buried underground and treat wastewater through digesting organic matter, separating materials, and slowly discharging the remaining liquid into soil or surrounding water. This bypasses the need for wastewater to process through public sewage systems.

Let’s look at this process in further detail:

    1. Piping: Wastewater is piped away from your property to the location of the septic tank, underground.
    2. Separation: The septic tank itself is a watertight container made of an impervious material, such as fibreglass, brick or concrete. It is here that the wastewater is stored long enough for bacteria to anaerobically digest organic matter and for the solid elements to settle out into sludge. Meanwhile, the oil components will float to the surface.
    3. Leach Field Treatment: Effluent then will exit the tank and seep into a leach field (otherwise known as a drainage field or soakaway). This area is rich in bacteria and oxygen, allowing for the further treatment of the water, ridding it of harmful bacteria and viruses.
    4. Clean Water Seeps Into Groundwater: Once the wastewater has been transformed into clean water, this liquid then escapes into groundwater, soil or surface water.

Treating water on site in this manner has environmental and economical benefits for a home or business owner, mainly because you avoid reliance on public sewer systems and the treated water can enrich and improve the health of your soil.

How do I empty my septic tank?

Regular maintenance and emptying by a professional company is vital for septic systems – neglect this, and the whole system will suffer, leading to big costs down the line.

During the separation process, sludge is formed at the bottom of the septic tank. Over time, this can build up and impede the performance of your drainage system. A septic tank should be emptied by a specialist every 12 months to maintain its effectiveness. However, if you notice that the effluent is a grey colour, or that your toilets and other internal appliances are sluggish, then this could indicate a septic tank in need of desludging.

ultimate septic tank guide

I have a septic tank: what items shouldn’t I flush down the drains?

If your premises is connected to a septic tank, you must ensure that certain substances don’t enter your drains via toilets, sinks or showers. These items and substances can poison the septic system and reduce its effectiveness. For example, try and restrict the amount of fat, grease and oil you pour away – instead, thoroughly wipe down crockery before washing it. You should also avoid pouring bleach down drains if you can, along with hygiene and sanitary products, nappies, cigarette butts, pharmaceuticals, paints, detergents, other chemicals, or anything that is not biodegradable. Whether you have a septic tank or not, these are useful tips to follow for good drainage practice.


Searching for qualified drainage experts to maintain your septic tank or cesspit? Here at Express Drainage Solutions, thanks to our fleet of fully-equipped tankers, we offer competitively-priced system maintenance and scheduled emptying to ensure your system is healthy and fully operational. For those needing a new system, we also supply high quality Klargester tanks, one of the leading brands on the market. To discover more about our services and our drainage tanks, simply get in touch today.


Want more information?Contact us today on 020 8979 5444

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