What is a drainage field?

This is the secondary treatment area following a septic tank or a sewage treatment plant, allowing the discharge to pass safely through and receive further treatment from the ground it passes.

They are often installed in paddocks, fields, or gardens. Drainage fields are a network of pipes that allow the partially treated water to pass via perforated pipes and shingle into the ground.

If you are in a flood zone, a drainage field may not be suitable due to the high groundwater levels typically found in these areas. When groundwater is close to the surface, it can interfere with the drainage field’s ability to absorb and filter wastewater effectively.

This excess water can saturate the soil, reducing its capacity to absorb additional wastewater from the system, which can lead to pooling, backups, or even contamination of surface water.

High groundwater can also cause untreated wastewater to surface during heavy rain or flooding, creating health and environmental risks. Alternative systems like raised bed or mound systems may be advised to maintain the drainage area above the water table for proper filtration and dispersal.