What is a soakaway system? Understanding its function and benefits
Known for being a great way to control surface water drainage and stopping excess water from penetrating your sewer system, a soakaway system has plenty of uses. As soakaway systems are increasingly being considered as a great long term solution for residential and commercial buildings as well as roads, it is worth exploring how they function and their benefits.
What is a soakaway system?
With soakaway systems becoming a more common natural solution, it is worth answering the question ‘what is a soakaway?’ Simply put, a soakaway system is a drainage system or underground unit created for rainwater run-off. It is designed to be a hole dug in the ground that is filled with materials such as rubble, stone or plastic crates. These crates have voids which permit a lot of water to filter through and go back into the ground.
Some soakaways are small with holes that are filled with granular material such as crushed rock, smashed brick or gravel. They require a PVC sheet or concrete blinding to be placed over the fill to stop topsoil being carried into the soakaway. Alternatively, large soakaways are made up of a pit lined with dry jointed or honeycomb brickwork. In order to determine what size of soakaway you should have, the area of your roof that will discharge into the soakaway will need to be calculated. This should also help you to determine how many crates you will need.
Furthermore, there are also different types of soakaway systems including drainage fields, bore hole soakaways, soakaway chambers, rubble filled pits and bespoke soakaway arrangements. Firstly, a drainage field is a network of perforated or slotted pipework that connects from the septic tank of a sewage treatment plant. It is optimised to disperse partially-treated effluent over a larger area.
Secondly, a bore hole soakaway is a construction found beneath the surface of the ground that collects excessive water from the ground’s surface and effectively drains it. It is also known as a deep bore soakaway, borehole soakaway or soak pit. As it is a specialist structure, it will require the assistance of professionals who will be responsible for installing it.
Moreover, a soakaway chamber is typically used in situations where there is not enough room for a drainage field despite the ground conditions being fitting for one. For this type of soakaway to be installed, an assessment of the ground needs to be carried out to test the suitability and depth of it.
In addition, a rubble filled pit is a trench that is filled with rocks. The aim of this type of soakaway is to prevent flooding by permitting the water to go through the soil. Nowadays, rubble filled pits are considered outdated and usually will be present at properties that were constructed before 1975 as they are fitted through a storm water drain. Although they are common in rural areas, soakaways can also be installed in the gardens of suburban homes to cope with waterlogged lawns.
Lastly, a bespoke soakaway arrangement is another option for those who cannot find a suitable soakaway system for their personal situation. However, it is also worth nothing that bespoke soakaway arrangements such as a single line deep trench arrangement will require the permission of the relevant authorities.
How does a soakaway system work?
Although the term ‘soakaway system’ is becoming recognised more, a lot of people still need an answer to the question ‘how does a soakaway work?’. This is especially crucial if they are considering installing one themselves.
When a hole is dug in the ground, it switches the course of the water to allow it to soak into the ground as opposed to flowing into a stream or sewer system. This system is put in place to facilitate the rapid and highly efficient drainage of water.
The crates that are placed in the hole will link the pit to guttering coming from your property. They will be shrouded by a permeable material that permits water through while simultaneously thwarting the entry of any debris. The system is optimised to guarantee a half empty time of 24 hours or less.
Components of a soakaway system
Once you have got the answer to the questions ‘what is a soakaway system?’ and ‘how do soakaways work?’, it is important to know what the components of a soakaway system are. Soakaway systems typically consist of screens, a catch pit, a septic tank, soakaway pit, and dung channels.
Soakaway screens are put in place to eradicate suspended solids and coarse matter found in the wastewater. The opening of a soakaway screen should never be too small as it may prevent the wastewater from moving through. Alternatively, it should never be too big as solid material will also pass through. It is also important to note that screenings can be frequently changed and they do not have a permanent place in the soakaway system.
Furthermore, the catch pit is another integral part of the soakaway system and its purpose is to gather the wastewater from the dung channels and to ease the process of getting rid of solid material. Its size needs to be big enough to stop the potential of water overflowing and to facilitate a proper screening of solid material. This solid material needs to be removed from the catch pit after each washing process.
In addition, the septic tank is a part of the soakaway system that is put in place to accelerate sedimentation and the decomposition of small solid particles. Of course, the purpose of the dung channel is to gather and transport wastewater to the catch pit as well as to stop rainwater overflow. It will need to be wide enough so that it can be maintained and have an appropriate gradient to enable self cleansing.
Benefits of soakaway systems
A soakaway system design has many benefits as it is an efficient and sustainable way of coping with contaminated or excess surface water with a low impact on the environment as it uses little materials and resources. It can also successfully stop the land surrounding your property from flooding, which can minimise any damage inflicted by the bad weather.
In cases that are sudden or unpredictable such as extremely bad weather, soakaway systems can also be installed retrospectively to cope with the aftermath, instead of needing to address the issue immediately. Once you do have a soakaway system installed, it is incredibly easy to maintain meaning that you don’t have to put in extra money or effort to do so.
In comparison to other ways of taking surface water away from sewer drains, soakaway systems are also cost-effective, especially if you live in a region that is likely to have a lot of rainfall and you need a solid solution. If you avail of the services of experts, soakaways can last for at least 25 years as long as they are safeguarded from vegetation nearby.
Furthermore, as there is so much bacteria in wastewater, there is a high likelihood that diseases can be caught in it. However, soakaway systems help to reduce the risks of waterborne diseases which can aid in protecting human life and public health. On top of this, there are no chemical treatments applied to the water before going back into the eco system, which reduces the likelihood of the surface water being polluted further before returning to the ground.
In addition, the actual process of installing a soakaway system is not complicated and can be carried out by experts who will supervise the entire process, from designing the soakaway system to installing it. Furthermore, soakaway systems such as the rubble soakaways are not an eyesore around your property as they are basically invisible. On top of this, these types of systems can be used as a solid water source for gardens and as a way to ensure the ground is moist.
Planning and designing a soakaway system
When planning and designing a soakaway system, it is important to take into consideration the size, its distance from nearby buildings and the state of the ground where you will be installing the soakaway. In this preparation period, you will need professionals to conduct appropriate tests so that they can gauge which system is the best for your property.
For example, in order to check whether the soil is permeable, a percolation test will need to be carried out. This will allow you to make sure that the water will be able to seep into the soil naturally and the system will be able to function properly.
A percolation test requires professionals to dig 300mm into the ground, underneath the proposed invert level of the distribution pipe. The hole is then filled with water to a depth of at least 300mm and left to sit overnight. After the night is over, the hole will be refilled and observed to gauge how long it takes certain levels of water to trickle away. This process will be repeated at least 3 times in 3 trial holes to obtain an average time which will influence the area size of the soakaway.
As assessment of the property will also need to take place to calculate the distance of the drainage field from obstructions, ditches, surrounding buildings and water abstraction points such as such as surface water and groundwater. At this stage, the soakaway size should also be determined so that it fits in with the size of your house and grounds.
Maintenance and inspection
Although soakways are designed to last a long time, they still require maintenance and inspection to ensure that they are prepped for long term functionality. With this in mind, it is recommended that a soakaway system is serviced and maintained every 12 months.
There are multiple problems that could threaten the performance of your soakaway system including damage that is inflicted to a septic tank. Septic tanks require frequent maintenance to ensure they are operating efficiently and effectively. The septic tank will need to be emptied to dispose of the sludge that builds up in order to allow the wastewater disposal system to be at peak condition. As well as the soakaway, septic tanks need to be emptied and services every 12 months. However, if a strong smell is exuding from the septic tank, this should alert you that it needs to be serviced sooner.
It is important to note that conducting regular maintenance of the septic tank is directly correlated to how long a soakaway system will last in the long term. This is why it is important to reach out to professionals who will guide you on how to set up a drainage system that lasts for years to come. Although no exact figure can be given with regards to how long your soakaway system will last, there is no doubt that servicing and maintaining it will permit the efficient draining of wastewater and drastically reduce the likelihood of any malfunctions in the future.
Soakaway solutions from experts at OMDI
At OMDi, we believe that the process of understanding and installing soakaways does not have to be difficult. Our in-house team are specialists in soakaway design and installation for both commercial and domestic properties throughout the U.K.
As a highly professional team, OMDI is committed to guiding you throughout the process of designing and installing a soakaway while working closely with you every step of the way. Whether you are looking for an initial consultation or a completion of an installation, we prioritise treating each customer as a unique individual while ensuring you are provided with the most efficient soakaway possible.
We have a myriad of high quality, bespoke drainage solutions that are optimised for both domestic and commercial properties. Whatever your requirements are, make sure to contact us today to discuss your needs with one of our experts. You can either fill out our contact form or give us a call on 01977 800 418 and we will be happy to assist you.