Drainage for tarmac drives in Dorset

How much does tarmac driveway drainage cost in Dorset?

Rates in Dorset follow the South West, about 3% above our UK midpoint.

Item	Guide price (inc VAT)
Linear drainage channel	£62–£124 per metre
Soakaway or crate unit	£670–£2,050 each

Towns we cover in Dorset

Postcode areas: BH, DT.

What is included?

Driveway drainage is the plan for where rainwater goes once it hits a sealed tarmac surface: the falls that move it, the channels or gullies that catch it, and the soakaway, border or approved drain that takes it away.

Falls set across the drive, typically 1 in 60 to 1 in 80
Linear channel at garages, doors or the bottom of a slope
Soakaway or crate unit sized to the area and ground
Runoff directed to borders or a permeable strip
Connection to an existing surface-water drain where allowed
No connection to the foul sewer

Rules in Dorset

In England, householder permitted development (Class F of the 2015 General Permitted Development Order) lets you lay a hard surface in front of a house without planning permission if it is porous, or if the rainwater is directed to a permeable area within the property. If the area is more than 5 m² and neither applies, you need permission. Standard dense tarmac is not porous, so a dense tarmac drive needs a lawn, border, channel to a soakaway or other permeable route for its water. Any new or widened crossing over the pavement needs approval from the highway authority (the county or unitary council).