Driveways & Planning Permission: the 5m² Rule

Written by the Farnborough Contracting Services team.
over 20 years on the drains and ground of north Hampshire and west Surrey.

This is the single most useful thing to know before you choose a driveway surface, and most people find out about it after they have already paid a deposit on the wrong one.

The rule in one paragraph

Since 1 October 2008 you have needed planning permission to lay a traditional impermeable driveway of more than five square metres at the front of a house, where the rainwater runs off onto the road. A permeable surface needs no permission at any size. So does an impermeable surface where the water is directed to a lawn, a border or a soakaway inside your own boundary.

Why the rule exists

Front gardens across the country were paved over through the 1990s and 2000s, and every one of them turned a patch of ground that soaked up rain into a hard surface that shed it straight into the road and then into the drains. Enough of them together overloads surface water sewers and contributes to flash flooding. The 2008 change to permitted development rights was the response.

It is worth understanding the logic, because it tells you how to satisfy the rule rather than just comply with it. What the rule cares about is where the water ends up. Keep the rain on your own land and you are outside the requirement. Send it to the highway and you need permission.

What counts as permeable

Government guidance names three surfaces specifically:

Gravel. Cheapest, drains freely, needs edging and a grid or membrane to stop it migrating and rutting.
Permeable concrete block paving. Looks like normal block paving. The difference is wider joints filled with a clean angular grit, and an open-graded sub-base underneath that stores and releases water rather than shedding it.
Porous asphalt. Tarmac with an open structure. Less common domestically but it works.

Resin bound is porous and drains through as well, though it needs a sound base beneath it, usually tarmac or concrete, and the permeability of the whole build-up is what matters rather than just the top layer. Resin bonded, which is a different thing, is a scatter of stone over a sealed surface and does not drain.

The other route: keep the water on your land

You can lay a completely impermeable surface, any size, without permission, so long as the rainwater goes somewhere on your own property rather than onto the road. Government guidance sets out the options and specifically says methods can be combined:

fall the surface to a lawn or border so it drains naturally
soak it away into the ground, in a properly sized soakaway
harvest it, into a tank or butts for storage and reuse
as a last resort, connect to a drain, which is the least favoured option and may need consent

In practice on a clay site we usually end up with a combination: a permeable surface plus a soakaway sized on a percolation test, because the surface can only pass water as fast as the ground beneath will accept it. Government guidance makes exactly this point, noting that clay soils may need a connection to roof water drainage.

What this means on the ground in our patch

Geology decides the design, and it changes sharply within a few miles here.

Where	Ground	What that means for a driveway
Camberley, Frimley, Bagshot	Bagshot Sands	Percolates well. Permeable paving over a soakaway works properly. Compact the sandy sub-grade thoroughly or the surface will rut.
Cove, Southwood, parts of Farnborough	London Clay	Poor percolation. Permeable surface plus a soakaway sized from a real test, or attenuation crates. This is why so many soakaways here fail in a wet autumn.
Guildford, Hog's Back, Alton	Chalk, variable	Often good, sometimes very poor on the same street. Test rather than assume. Watch for solution features in chalk.
Woking, Byfleet	Low lying, high water table in places	A saturated ground will not accept surface water at all. Attenuation or a connection rather than a soakaway.

When you need permission whatever the surface

The five square metre rule is not the only thing that can catch you. Permission is needed regardless of permeability where:

the property is listed, or in a conservation area, which covers a lot of central Farnham
permitted development rights have been removed, common on newer estates and easy to miss
the property is a flat or maisonette rather than a house
you are also forming a new access onto a classified road, which is a highways matter as well

And the driveway is only half the job if you need a dropped kerb to get onto it. That is a separate application to a different authority, on a different timescale, and it is worth reading how dropped kerbs work in Hampshire and Surrey before you plan the sequence.

Is permeable worth the extra?

It does cost more per square metre. Permeable blocks are a different product, and the sub-base underneath them is an open-graded stone that stores water rather than shedding it, so there is more material in the ground. We will price both specifications on your own driveway so you can see the difference on your job rather than a national average.

What the extra buys you:

No planning application, and no application fee, at any size
No puddle at the low point, and no sheet of ice there in January
No water running across the pavement, which is what annoys neighbours and councils
Less load on a surface water system that in some of these towns is already at its limit

There is one honest caveat. Permeable paving needs its joints kept clean. Silt and leaf litter gradually clog the surface, and it wants brushing and an occasional vacuum sweep to keep working. It is a small maintenance job, but it is not zero, and anyone who tells you otherwise is selling.

One thing to check before publishing your plans anywhere

The rules above come from government guidance on permeable surfacing of front gardens, which dates from the 2008 change. The underlying permitted development order has since been replaced, so if you need the exact legal class reference for a planning application, get it confirmed with your local planning authority rather than relying on any website, including this one. The practical rule, permeable is fine and impermeable over five square metres draining to the road is not, is what matters for choosing a surface.

Questions people ask

Do I need planning permission for a driveway?

Not if the surface is permeable, such as gravel, permeable block paving or porous asphalt, or if the rainwater is directed to a lawn, border or soakaway within your own boundary. Size is irrelevant in that case. You do need permission for a traditional impermeable surface over five square metres at the front of a house where water runs off onto the road.

What counts as a permeable surface?

Government guidance names gravel, permeable concrete block paving and porous asphalt. Directing the rainwater to a permeable area such as a lawn, a border or a soakaway also satisfies the rules, even where the surface itself is not permeable.

Does permeable paving work on clay?

It needs help. On clay the water cannot soak away quickly, so a permeable surface has to drain to a properly sized soakaway, an attenuation crate or, as a last resort, a connection to a drain. Government guidance specifically notes that clay soils may need connection to roof water drainage.

Is permeable paving more expensive?

The blocks and the open-graded sub-base do cost more per square metre than standard block paving. Against that you avoid a planning application and its fee entirely, at any size, you avoid the puddle and the sheet of ice at the low point, and you are not sending your surface water onto the highway. We will price both on your job so you can see the difference.

Where this comes from

The rules, fees and figures on this page are taken from the sources below. Fees change, so check the current figure before you send anyone money.

This is general information about how the rules work, not advice on your particular property. If something here matters to a purchase or a dispute, get it checked on your own facts.

Why a permeable driveway needs no planning application, at any size