Borehole Soakaway
Borehole soakaways are an effective method for managing surface water and promoting sustainable drainage. By directing rainwater or runoff into a deep, perforated borehole, water gradually infiltrates the surrounding soil, reducing flooding risk and recharging groundwater. Unlike traditional soakaways, borehole systems can handle larger volumes in limited spaces, making them suitable for urban environments or areas with poor surface drainage. They are typically constructed using durable pipes or casings, often lined with gravel, to ensure long-term performance. Proper design and installation are critical to maintain efficiency, prevent blockages, and protect water quality.
What is a Borehole Soakaway?
A deep, narrow vertical shaft (usually 3–30 metres deep) that discharges surface water directly into deeper, more permeable strata such as gravel or chalk layers. Often used when the topsoil is clay or poorly draining.
How it works:
Water is directed from the surface drainage system down the borehole, where it seeps into the lower permeable layers.
At UK Drainage Design, we do not directly design borehole soakaways, as their planning and construction require specialist geotechnical engineering expertise. These systems demand detailed site investigation and technical analysis to ensure safety, efficiency, and long-term performance. While we do not provide the design ourselves, we are happy to recommend trusted, qualified geotechnical engineering consultants who can guide you through the process and deliver a reliable, compliant solution.
Advantages / Limitations
Advantages:
- Ideal for areas with impermeable surface soils.
- Provides deep infiltration and prevents surface flooding.
- Can handle large volumes if designed properly.
Best for:
- Sites with clay soils or limited land area.
Limitations:
- More expensive to drill and install.
- Requires specialist design and ground testing.
- Must comply with groundwater protection regulations (Environment Agency approval may be needed).