Drainage Field Soakaway Systems
Soakaway systems have a drainage field, which is a shallow, covered, excavation made in unsaturated soil. Pre-treated wastewater is discharged through piping onto porous surfaces that allow wastewater to filter though the soil. The soil accepts, treats, and disperses wastewater as it percolates through the soil, ultimately discharging to groundwater.
Stage 1
Percolation Test
A percolation test is required to determine whether a soakaway system installation can be carried out at a property. The Percolation test is to identify if the soil is suitable, it will also determine the size of the drainage field
Stage 2
Calculate Vp
The Vp is calculated using the measurement of soil porosity gained from the percolation test and the amount of people served by the tank
Stage 3
Excavate and Install Drainage Field
Once the size has been established, the correct area will be excavated, and slotted drainage pipe installed in a continual loop
Drainage fields
A drainage field/soakaway system is designed to spread partially treated effluent over a larger area. A septic tank must connect to a drainage field, as septic tank discharge cannot go directly into a watercourse. A sewage treatment plant system can also be connected to a drainage field if a nearby watercourse cannot be located for discharge. The drainage field will provide even further treatment to the settled effluent and disperse it safely into the ground. A suitable porosity test will ensure that the receiving ground is suitable for the installation of a drainage field.
Drainage fields typically consist of a system of slotted irrigation pipes which allow the effluent to percolate into the surrounding soil. Biological treatment then takes place naturally in the aerated layers of soil to ensure correct discharge and treatment of foul water has occurred.
The appropriate design of a drainage field is covered in BS6279, and is also well documented in Building Regulations Document H and the Environment Agency PPG4 Document. Albeit less common than previously, drainage fields still offer a viable route for those required a discharge of treated/partially treated effluent.
Our Working Process
Get In Touch
Give us a quick call and explain if you require a new drainage field or replacement of an existing field.
Percolation Test
We require a percolation test to be carried out before any soakaway installation as a requirement from building control, this will determine the size of the required field.
Evaluate figure and provide a quote
Our engineers will evaluate the figures of the percolation test and calculate the require size of the field and provide a quote for this.
Excavate and Install
We will then excavate the required area, install the drainage field pipe, have inspection from building control and then reinstate the area.
