The short answer
A french drain in the UK typically costs £25–£60 per linear metre installed, so a short run for a small garden often falls around £800–£2,000 and a longer system for a larger plot can run to £2,500–£4,500. A french drain is a gravel-filled trench with a perforated pipe that intercepts water moving through the ground and carries it away to a soakaway, watercourse or surface-water drain. It suits gardens where water sits or runs across the surface, or where a damp area needs intercepting before a wall or patio. The price moves with the length, depth, soil type and access, and where the collected water is sent.
A french drain is one of the most common garden-drainage fixes, but the price varies widely with length and ground. Here is what it typically costs and what changes the figure.
Typical UK costs
- Per linear metre£25–£60 installed
- Small garden run~£800–£2,000
- Larger system~£2,500–£4,500
- What it isgravel trench + perforated pipe
- Sends water tosoakaway / watercourse / drain
What moves the price
- Length: you pay largely per metre of trench, so the run length is the biggest driver.
- Depth: a deeper drain to catch a high water table means more excavation and aggregate.
- Soil & access: clay and hand-dig conditions cost more than free-draining soil a digger can reach.
- Where it outfalls: a nearby soakaway is cheaper than a long pipe run to a watercourse or a new soakaway dug at the end.
| Item | Typical figure | Notes |
|---|---|---|
| French drain installed | £25–£60 / m | by depth, soil & aggregate |
| Small garden run | ~£800–£2,000 | short interception run |
| Larger system | ~£2,500–£4,500 | longer or multiple runs |
| Soakaway at the end | £600–£3,000 | if no watercourse to use |
Indicative UK figures for guidance. Sources: Checkatrade and MyBuilder cost guides.
When a french drain is the right fix
A french drain works best where water moves through or across the ground — a slope shedding water onto a lawn, a damp strip beside a path, or surface water that needs intercepting before it reaches the house. It is less suited to a flat, clay-bound garden where the water simply will not move, which may need a wider land-drain network feeding a soakaway, or regrading. A specialist should diagnose why the garden floods before recommending a french drain, because the wrong fix in the wrong place rarely solves a boggy lawn.
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Frequently asked questions
How much does a french drain cost per metre?
Typically £25–£60 per linear metre installed in the UK, with the run length, depth, soil type and access all moving the figure. A short small-garden run often falls around £800–£2,000.
What is a french drain?
A gravel-filled trench with a perforated pipe that intercepts water moving through the ground and carries it away to a soakaway, watercourse or surface-water drain.
Will a french drain fix a waterlogged lawn?
It helps where water moves across or through the ground, but a flat clay garden where water simply sits may need a wider land-drain network and a soakaway, or regrading. A specialist should diagnose the cause first.
Sources & further reading
Figures on this page are typical UK ranges drawn from published sources and depend on your specific garden and ground. They are guidance, not a quotation.