Every hard surface collects rain, and that water has to go somewhere. On a well-planned drive or patio it runs gently away from the house, into a channel drain, a border, a lawn or a soakaway. On a poorly planned one it pools by the front door, runs back against the wall, washes the sand out of block paving or floods onto the pavement.
Drainage can be part of a new driveway or patio, or a job on its own to fix an existing surface. Tell us what is happening and add photos, ideally after rain. You get an indicative price range straight away, and we pass your enquiry to one local specialist, who confirms a fixed price.
What it costs
| Job | Indicative price |
|---|---|
| Channel drain (linear drain), per metre | £60–£100 |
| Soakaway | £600–£1,200 |
| Channel across a 5m drive entrance | about £300–£500 |
| Channel across the drive plus a soakaway | about £900–£1,700 |
Channel drain prices include cutting in, a concrete bed and haunching, the grating and connecting to an outlet. Soakaway prices cover digging the pit, the crate or rubble fill, membrane wrap and the pipe run from the drain. Drainage on its own starts from about £600. On a new two-car block drive at the front, a soakaway can take the total from £3,550–£5,730 up to about £6,930. The driveway cost per m² guide shows how drainage fits into a full driveway price.
The 5m² front-garden rule
In England, if more than 5m² of a front garden is paved with an impermeable surface, the water must be directed to a permeable area on your own property, such as a lawn, border or soakaway. Otherwise the paving needs planning permission. Letting it run onto the pavement or into the road does not meet the rule.
That is why front drives in tarmac, imprinted concrete or standard block paving usually need a channel drain and soakaway, or a fall towards a planted area. Permeable surfaces such as resin-bound, gravel and permeable block paving let water soak through and generally do not. Our guide to the 5m² rule explains it fully.
Channel drains
A channel drain is a narrow trough with a grating on top, set flush with the surface. It catches water running across a drive or patio and carries it to an outlet. Common positions:
- Across the drive entrance, so water does not run onto the pavement.
- Along the house wall, where a drive or patio falls towards the house or sits close to the damp-proof course.
- Across the bottom of a slope, where a sloping drive meets a garage or door.
For drives, the channel and grating must be rated for car loads. Plastic channels with light-duty gratings are for patios and paths only.
Soakaways
A soakaway is a pit filled with plastic crates or clean rubble, wrapped in a membrane, that holds water and lets it soak slowly into the ground. It has to be sized for the paved area, and placed well away from the house, commonly at least 5m from a building.
Soakaways depend on the ground. On free-draining soil they work well. On heavy clay, which is common across Birmingham and the Black Country, water drains slowly and a soakaway may need to be larger, or may not be suitable at all. A proper job starts with a percolation test to see how fast the ground drains.
Where the water must not go
Surface water from a drive or patio must never be connected to a public sewer without the water company's consent. In most of the West Midlands that is Severn Trent. Connecting to a foul sewer is not allowed, and connecting to a surface water sewer needs permission.
Any job where the drainage might run into a public sewer, or where the outlet is unclear, is priced after a free site visit so the specialist can check what is underground.
Fixing an existing surface
Water pooling on an existing drive or patio usually comes from:
- No fall, or the wrong fall, often because the base has sunk.
- Blocked or missing drains, or gratings full of silt and leaves.
- Sand washed out of block paving joints.
- A drive laid too high, at or above the damp-proof course.
Sometimes a channel drain solves it. Sometimes the surface has to be lifted and relaid to the right levels, which is priced as part of a new driveway or patio. Photos after rain show the specialist exactly where the water sits.
Local specialists cover Sutton Coldfield, North Birmingham, Solihull, South Birmingham, Edgbaston and Harborne, Lichfield and Tamworth, Walsall, Wolverhampton, Dudley and Stourbridge and Coventry.
What to photograph for a quote
Good photos mean a closer price, and a shorter visit to measure up. How to measure.
- The whole fence line or area, end to end, standing back as far as you can
- From above if you can: an upstairs window shows the size and levels best
- The way in from the road: the drive, side gate, steps and where a lorry could park
Questions about driveway drainage and soakaways
Do I need drainage for a new driveway?
Every driveway needs somewhere for water to go. A permeable surface lets it soak through. An impermeable surface at the front over 5m² needs a channel drain, soakaway or a fall to a border on your own land, or planning permission. See do I need planning permission for a driveway.
Can I connect my drive to the drain in the road?
Not without consent. Surface water must not go into a public sewer or highway drain without permission from the water company or highway authority. The specialist will look at other options first.
What size soakaway do I need?
It depends on the paved area and how quickly your ground drains. A percolation test gives the answer. The specialist sizes it on site.
Will a soakaway work on clay?
Sometimes, but more slowly. A larger soakaway, or directing water to a lawn or rain garden instead, can work better. In some cases a permeable surface is the simpler answer.
Why is my block paving sinking where the water collects?
Standing water softens the sub-base beneath. Adding drainage stops it getting worse, but the sunken area usually needs lifting and relaying. See why cheap driveways fail.