Percolation Tests

Percolation tests and soakaway tests determine whether ground is suitable for soakaways or waste water treatment plants. They are widely used to support planning and development applications, using a natural drainage system to store and dissipate effluent to ground.

A percolation test is an essential part of any off mains drainage system installation, percolation test results are often required by building control to demonstrate the ground conditions are acceptable and the soak away has been designed for the individual site location.

What is a Percolation Test?

Soakaway systems can be used to take the wastewater from either a septic tank or a sewage treatment plant. Its a network of perforated or slotted pipework which allows the waste water to percolate safely through the ground without causing pollution.

A percolation test is a way of assessing the ground conditions at a property to determine what type of soakaway arrangement might be suitable. If the ground is found to be suitable for a drainage field, a percolation test also helps to determine how big it needs to be.

What does it involve?

The percolation test itself involves digging three test pits in the area of ground where you are planning to install a soakaway system, and measuring the speed at which the water drains out of the pits.

When are they required?

A percolation test should always be carried out if a drainage field or soakaway is due to be installed at a property. A percolation test is not required for a sewage treatment plant to discharge straight to a ditch or a watercourse.

If a property is not connected to a main sewer, it will be connected to an off mains drainage system such as a septic tank, sewage treatment plant or cesspit.

If the property has a septic tank or a sewage treatment plant, the waste water from the tank will discharge either to a soakaway system such as a drainage field or to a watercourse. It’s good to be aware of the General Binding Rules here, which determine whether you are legally allowed to discharge to a watercourse – you can read our

If a septic tank or treatment plant is to discharge to a drainage field, a percolation test will be required.

What is a drainage field?

The purpose of a drainage field is to allow the wastewater leaving the septic tank or treatment plant to safely percolate into the ground. It is the percolation of the waste water through the subsoils which provides a form of treatment of the water, and allows it to pass into the local environment without causing pollution. A drainage field is typically comprised of a network of perforated or slotted pipes, which allow the waste water to pass into the surrounding sub soils.

Percolation tests are essential to ensuring that the correct drainage system is installed for a waste treatment plant, if you require a new tank or are having trouble with an existing soakaway please contact Enviroguard.

Get in touch

Enviroguard are experts in drainage surveys, and have all the expertise, experience and equipment necessary to provide a comprehensive service. Simply call us on 01539720950. Or, alternatively, please use our online enquiry