# What is a Permeable Paver?
**A permeable paver (also called a buffer brick or bufferklinker) is a specially designed paving unit that allows rainwater to infiltrate through its surface or joints into the sub-base below. These pavers are a key component of sustainable urban drainage systems (SUDS), helping to reduce surface runoff, prevent flooding, and recharge groundwater.**
## How permeable pavers work
Permeable pavers manage stormwater through two primary mechanisms:
### Through-the-surface infiltration
Porous pavers are manufactured with an open aggregate structure or enlarged pore network that allows water to pass directly through the brick material itself. Infiltration rates typically range from 50 to over 1,000 litres per square metre per hour.
### Through-the-joint infiltration
Some systems use conventional dense pavers with widened joints (6–10 mm) filled with open-graded aggregate. Water drains between the pavers rather than through them.
## Sub-base design
Below the pavers, a layered base of crushed aggregate provides temporary water storage (buffering) and controlled infiltration into the subsoil. Typical layers include:
– Bedding layer of fine crushed aggregate (30–50 mm)
– Base course of open-graded gravel (150–400 mm)
– Optional geotextile separation layer
– Compacted subgrade
## Advantages
– Reduces peak stormwater runoff by up to 80%
– Lowers the burden on municipal sewer systems
– Filters pollutants from surface water
– Helps prevent urban heat island effects
– Meets increasingly strict water management regulations
## Applications
– Residential driveways and parking areas
– Commercial and public car parks
– Pedestrian paths and squares
– Low-traffic urban streets
– Green infrastructure and climate-adaptive urban design
## Related terms
– Sustainable urban drainage system (SUDS)
– Infiltration crate
– Water-permeable surface
– Attenuation tank
– Rainwater harvesting
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