The Flood Hub

This blog has been written by The Flood Hub People.

Paving over driveways can be practical and visually appealing, but it can also reduce your property’s ability to manage surface water and increase the risk of flooding. This blog covers the options available, planning requirements and things to consider when installing a driveway, rain garden or soakaway.

 

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Background: Why Surface Water Matters

We spoke to a couple who had recently experienced flooding, their conversation highlighted a common dilemma many homeowners face. One partner wanted to install a tarmac driveway for convenience and aesthetics, while the other understood that covering a lawn or garden with an impermeable surface can reduce natural drainage and increase surface water runoff.

When rainwater cannot soak into the ground, it flows across paved areas and can overwhelm local drains and sewers. This contributes to surface water flooding, which is one of the most common causes of property flooding in the UK. By managing water responsibly within a property boundary, homeowners can reduce the risk of local flooding, prevent damage to gardens and roads and help maintain a more sustainable water cycle in urban areas.

 

Planning Requirements for Driveways

Before installing a driveway, it’s important to know the planning rules for front gardens:

• Planning permission is required if you lay a traditional impermeable driveway over more than 5m², as water cannot drain naturally.
• No planning permission is needed if the driveway uses permeable (or porous) surfacing or directs rainwater to a lawn, border, or other permeable area.

 

Points to Consider

• During a heavy storm, an average driveway can collect over 500 litres of rainwater, roughly enough to fill three bathtubs.
• Using Sustainable Drainage Systems (SuDS) can help manage water through slow release, filtration, and groundwater recharge, reducing flood risk and pollution.

 

 

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Permeable Paving Options

Permeable paving allows surface water to penetrate through the surface and either be stored temporarily or infiltrate into the ground, helping to reduce surface water runoff and the risk of local flooding. There are several options to consider:

 

Resin Driveways

Resin driveways are popular for their hardwearing, low maintenance and attractive finish. They can also offer a fully permeable solution if installed correctly. There are two main types:

• Resin Bound (Permeable): Aggregate is mixed with resin before being laid, creating a smooth, durable surface with tiny gaps between the pieces of aggregate. This allows water to permeate through the surface and into the sub-base. To be SUDS compliant, a permeable base and sub-base are also required, typically made from MOT type 3 and an open course binder.
• Resin Bonded (Non-Permeable): Aggregate is scattered on top of a resin layer, creating a rough finish. Water cannot pass through, so this is not suitable for SUDS purposes.

 

Grass or Gravel Pavers

These grid-based systems are filled with grass or gravel, offering a load-bearing surface for vehicles while allowing water to drain naturally. They are ideal for driveways, overflow parking and garden paths, blending seamlessly with landscaping.

 

 

Permeable Interlocking Pavers

Concrete or stone blocks designed with gaps for water to infiltrate. They are strong enough for vehicular traffic and often installed with sand or gravel infill, combining durability with drainage benefits.

 

Porous Resin-Bonded Aggregates for Walkways

A thinner version of resin bound surfacing, perfect for paths, patios, or small outdoor areas. When laid on a permeable sub-base, they allow water to drain effectively.

 

Permeable Brick Paving

Traditional brick laid with gaps filled with permeable sand or gravel. This maintains a classic look while ensuring water infiltrates the ground, reducing runoff.

 

 

Reinforced Gravel Systems

Gravel is laid over a stabilising grid to prevent movement while remaining fully permeable. This option works well for driveways, garden paths, or parking areas and is cost-effective and environmentally friendly.

 

 

Permeable Block Paving

Permeable block paving, often made from concrete or clay, allows water to pass between the blocks and infiltrate through a permeable sub-base. These are ideal for driveways, paths and small patios, providing a traditional look while still offering sustainable drainage benefits.

 

 

Benefits of Permeable Paving

• Helps prevent localised flooding and water pooling on driveways, paths and nearby roads.
• Reduces pressure on public sewer systems, lowering the risk of blockages and sewer-related flooding.
• Supports groundwater recharge, maintaining a natural water cycle and helping gardens and green spaces thrive.
• Can improve the health of surrounding soil and vegetation by allowing rainwater to naturally infiltrate rather than run off.
• Can be integrated with other Sustainable Drainage Systems (SuDS), such as soakaways, rain gardens, or water butts, for maximum efficiency in managing stormwater.
• Helps properties comply with planning regulations on impermeable surfaces and can even increase property value by demonstrating flood-conscious design.
• Contributes to sustainable urban drainage, reducing pollution entering rivers and streams and supporting environmental resilience.

 

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Traditional Materials with Permeable Solutions

Even traditional surfacing materials like concrete or asphalt can be adapted to help manage surface water effectively. By designing your driveway or path with water management in mind, you can reduce runoff and prevent contributing to local flooding.

For example, the surface can be laid with a slight fall or gradient to direct water into a collection or drainage system, such as:

• Soakaways – these are lined with a membrane and filled with gravel, rocks, or drainage crates to create a void where water can slowly infiltrate into the ground. Read more on soakaways on our SUDs page.
• Rain gardens – depressions planted with shrubs, flowers, or grasses that may stay dry for long periods. They collect surface water during rainfall, allowing it to either infiltrate into the soil or evaporate naturally. Read more on Rain Gardens on our SUDs page.

 

Roof water can also be diverted into these systems by connecting drainpipes, further reducing the amount of water entering the public sewer network.

Many water companies charge for handling rainwater that enters the sewer system, either as part of a standing charge, based on your property’s rateable value or linked to your property type. By preventing roof and surface water from reaching the sewers, you may qualify for a surface water drainage rebate from your water company, which can reduce future charges and in some cases refund previous payments.

 

 

For more information with good links and tips on this subject, visit ‘Guidance on the permeable surfacing of front gardens’ here, or explore the Unpave the Way Project.