Driveway drainage and SUDS in Glasgow

What are SUDS and why do they apply?

Sustainable drainage systems manage rainfall close to where it falls instead of piping it to the sewer, and Scotland applies SUDS principles widely to new hard surfacing.

Discharging a new driveway to the combined sewer or the public road is the outcome the rules exist to prevent. Scottish Water and the council both have an interest in surface water leaving your plot.

What drainage options work on a Glasgow driveway?

• Permeable block paving with open-graded sub-base acting as attenuation
• Resin-bound surfacing over a permeable base
• Soakaway crate or rubble pit sized to the driveway area and ground infiltration rate
• Linear channel drain at the threshold, discharging to a soakaway
• Falls directed to a planted border, rain garden or lawn area

When does a soakaway not work?

A soakaway fails in clay ground with poor infiltration, close to foundations, or where the water table is high.

• Keep soakaways at least five metres from building foundations
• Carry out a percolation test where the ground is heavy clay, which is common across parts of Glasgow
• Use attenuation with a controlled outfall where infiltration is not viable

How are falls set on a driveway?

A driveway is laid to a fall of roughly 1:60 to 1:80 away from the building.

Water must never be directed towards the house or across the public footway. Where the ground slopes towards the property, a threshold channel drain is essential rather than optional.