How much does a French drain cost to install?

French drains are used as a form of land drainage and are named after Henry French, the 19th-century American farmer who developed and popularised them.

French drains are one of many drainage systems used to prevent water logging and an excess of surface water. They consist of a trench dug, at a gradient, into the ground, lined with membrane, filled with aggregate and, usually these days, a perforated drainage pipe. 

They are a great way to transport surface water away from walls and for many people they are the ideal solution in gardens or driveways prone to flooding. They are not the same as soakaways, which are a pit in the ground into which you run your rainwater drainage.

How much does a French drain cost to install?

Will Temperley, MD of Fortis Foundations, says labour costs typically range from £35 to £75 per hour, depending on the contractor’s experience and where you live.

He adds: “Installation can take between one to three days. In addition, the cost of materials including gravel, landscape fabric, PVC or perforated pipe, is around £7 to £15 per metre.

“Combining labour and materials, you can expect to pay approximately £45 to £90 per metre.”

If you are thinking of doing it yourself and hiring a digger, this can cost £75 to £160 per day if it is a mini excavator or a trencher. The operational costs are between £250 to £350. Furthermore, purchasing the necessary materials can cost £10 to £30 per metre.

“You also need to take into account additional tools to hire or purchase such as shovels, rakes, and compaction equipment which will all add to the overall expense of a project,” Will says.

The tools needed when installing a French drain are a spade or mini digger, wheelbarrow, a perforated pipe, geotextile membrane, and aggregate.

What can increase French drain costs?

Will says there are also factors you need to consider which can increase the costs of a French drain installation, for example, the depth and width of a trench.

“Deeper or wider trenches require more excavation, therefore resulting in more labour and material costs,” he said. “The type of soil can also increase costs if it is hard or rocky which can be more difficult to dig and so take more time. Limited site accessibility can also cause a strain on time and money.”

Pipe material and size are another factor – higher-quality or larger-diameter pipes are more expensive. Finally, longer drains require more materials and labour and post-installation landscaping or surface restoration, which can add to the total cost.

Will said: “French drains require periodic maintenance to remain effective, which should be factored into the long-term cost. Regulatory compliance is also imperative to consider. Ensuring the installation complies with local building regulations might incur additional costs.

“Moreover, it is advisable you have a professional assessment of the property to determine the most efficient drainage solution, which may add to the initial cost, but ensures effectiveness and compliance which can ultimately save you time and money.”

Is a French drain cheaper than other drainage types?

There are alternatives you can look at if French drains don’t meet your property’s needs and budget. Soakaways can be cheaper or more expensive than French drains depending on the size and complexity. Building a soakaway typically involves less piping but may require more extensive excavation and materials like rubble or crate systems.

“However, French drains are often preferred for their effectiveness in managing surface water and are cost-effective in the long term, especially in areas prone to waterlogging,” Will adds.

Soakaways, depending on various factors, cost £13 per tonne of hardcore, and labour costs for excavation run to roughly £180. Homebuilding and Renovating has a detailed breakdown of drainage costs if you need further information.

Will Temperley

Will Temperley founded Fortis Foundations in 2020, bringing over 20 years of rail and construction industry experience to the business.  

Fortis Foundations provide civil engineering products and services, specialising in foundations and piling to the rail, civils, energy, residential and water sectors. The family-run business is renowned for delivering safe and sustainable solutions at the forefront of innovation and technology.

In 2022, Fortis launched its sister company, Fortis EV (Electric Vehicles), becoming a strong supplier in the installation sector.