What is a Soakaway?

A soakaway can have various meanings when associated with land drainage.

In this instance we are referring to a soakaway attached to a septic tank or sewage treatment plant.

The soakaway has been around for hundreds of years.

If the septic tank is the heart of your sewage system, then the soakaway is the capillary system of the septic tank sewage system.  The soakaway allows all the liquid to drain off from the septic tank into the sub soil naturally.  Soakaways come in various shapes and sizes.  The most common soakaway is the ‘herringbone’ soakaway.  Generally the soakaway consists of a network of perforated drainage pipes and is connected in a circuit.  This allows the effluent from the septic tank to slowly seep away into the ground over time. Also they are a lot more reliable.  For instance, because they have many branches or veins interwoven into their design, if any or one of the pipes should become blocked over time then the rest of the soakaway will still continue to function.

Other designs are the soakaway pit.  Basically a large hole is dug and filled with gravel, shingle, builders rubble or other forms of medium.  The sewage effluent is then discharged into the pit.  These pits are somewhat outdated nowadays because if they fail to stop working then a new pit will have to be dug.

Soakaway construction can vary in size, shape and design.

Below is a herringbone design. copyright aa biotech waste solutions

The soakaway has one primary function, and that is to make sure that any liquid discharged into it soaks away into the ground.

How is a soakaway constructed?

The construction of a soakaway is simple in design.  The soakaway is usually constructed in two ways.

1) A reasonable size hole is excavated and filled with medium.  The medium used can vary considerably.  Some use bricks, crushed bricks, gravel, rubble, wood, shingle, piping, storm crates e.t.c.

The reason medium is used is to create a cavity in the ground.  The liquid fills the cavity and then slowly drains away over time.  The larger the hole, the greater the effectiveness of the soakaway.

2) Another way is similar to a french drain in construction.  A single trench or a series of trenches are excavated.  The trench or trenches are then filled with medium with in the Uk is generally 20-30mm shingle or gravel.

The perforated soakaway drainage pipe is then laid upon the bed of shingle, and then more shingle is put  back on top of the pipe.

A membrane is then laid on top of the of dpipe to stop soil and other debris entering the drainage pipe.  Finally the trench is back filled with soil.

Typical Soakaway Drainage Construction

As the liquid is discharged into the trenches it seeps away into the soil over time.  In many instances these trenches can be joined together to complete a circuit.

Generally the term for this kind of soakaway is called a ‘herringbone design’.

Years ago clay piping was used to carry the liquid effluent along the trenches.

Clay Soakaway Pipe

Today plastic piping is used that has perforations in the pipes.

These perforations allow the liquid effluent to seep out as it travels along the pipe.

All soakaways generally work by gravity, in that the liquid naturally flows through the soakaway in a downward direction.

In the UK there are now clear direction and guidelines when installing a new soakaway which is made available in section H of the UK building regulations and in material provided by the the Environmental Agency.  Failure to comply with these laws and regulations can result in serious prosecution.

Klargester have also brought out a new product called Ezy Drain.

In a nutshell this product is a complete soakaway kit.

All you have to do is dig the trenches, and lay into the trench the soakaway pipe.

EZY DRAIN

 

 

 

 

Once the soakaway pipes are laid, you then cover them with a breathable membrane, and fill the trench back in with soil.

You then have a soakaway that will last for 50 years.  For more information on Ezy Drain soakaway kits contact us on 0800 907 0051 or visit www.theseptictankshop.co.uk.

 

Soakaway Drainage Problems

The general problems associated with soakaway is that they become blocked or collapse over time.  Blockages generally occur when solids, sludge or other debris from the septic tank, cesspit or sewage treatment plant enter the soakaway.

Other common problems are root infestation, pipe collapse or if the soil around the soakaway has become clogged up with sludge discharge from the septic tank, cesspit or sewage treatment plant over the years.

Soakaway Blockage

 

 

 

 

 

 

 

 

 

 

If the soakaway is around 10 to a hundred years old and has developed serious symptoms of blockages or  signs of being clogging up then generally a new soakaway must be installed.

The general symptoms associated with failed soakaway is liquid effluent rising to the surface of the ground, or a dark and smelly discolouration of the grass in or around the sewage system.

Effluent rising to the ground

 

 

 

 

 

 

Or another symptom is that the septic tank, cesspit or sewage treatment plant needs emptying more and more frequently.

We specialise in repairing and installing sewage drainage soakaways, whether you live in an old or new property.

For free impartial advice please call us on 0800 907 0051.