15 August 2025
Does your garden turn into a mini lake every time it rains? If so, you’re not alone. Poor drainage is a common issue in the UK and with more heavier deluges that can sometimes last longer than expected it is becoming more and more of an issue. Especially if you own an older property or one built on clay-heavy soils. So what is one of the most effective solutions? A French drain.
At PM247, we’ve helped countless homeowners resolve their garden drainage issues with this simple but clever system. So in this guide, our expert drainage specialists have provided you with all the information that you need to know about French drains.. We’ll explain what a French drain is, why you might need one, and how to install a French drain yourself, should you feel up for the challenge. Below is a table of contents to make it easier for you to navigate the information.
So let’s diffuse two of the biggest fallacies straight away. Firstly, a French drain isn’t French (oddly enough), and secondly, it’s not really a drain in the traditional sense either. Confused? You shouldn’t be. Put simply, a French drain is essentially a gravel-filled trench that contains a perforated pipe, which is designed to redirect surface water and groundwater away from problem areas.
Water should naturally soak into your garden soil – unless that soil is compacted, or another common cause is that the ground or your garden doesn’t slope away from your home, leaving the water nowhere to go. Over time, standing water can damage your plants, cause slippery surfaces, or even seep into your foundations. A French drain gives that water an escape route and helps it drain away.
If after rain your garden stays soggy, pools water near the house, or suffers from water damage around patios, garages or sheds – a French drain could be the fix. It’s ideal for sorting out soggy lawns, damp patches, or water build-up near foundations.
Thinking about installing a French Drain? Call PM247 on 08082 504 203, or book a visit online and let the professionals take care of it for you.
The benefits of a French drain are numerous, however heres some of the reasons that our team likes them in particular.
There are a few things that you need to consider before attempting to put in a French drain. Here’s some of the key considerations:
You’ll need a fall of around 1% – that’s 1cm drop per metre of length. Use a line level, string and stakes to plan it out before digging.
Direct it to a garden soakaway, rain garden, gravel sump or an existing surface drain. Avoid directing it onto neighbouring land or public footpaths.
Yes. Use local ‘dial-before-you-dig’ services or maps to avoid hitting gas, water, or electric lines when you start excavating.
You can install a French drain yourself if you’re comfortable with a bit of graft, digging and DIY. You’ll need plenty of kit, and below is a step-by-step to help you get it right:
Tools You’ll Need:
Materials You’ll Need:
Perforated pipe for French drains
Image courtesy of Drainage Central.
Step 1: Start by Marking Out the Trench
Use marking paint or string to outline where your French drain will go. Make sure it’s running from the wet area to the planned outlet and that there’s a consistent downward slope (double check the points above).
Step 2: Dig the Trench
The trench should be around 15-20cm wide and at least 45-60cm deep, depending on the water issue. Use a spirit level or line level to maintain the slope. How long it is depends on how far you have to move the water.
Top tip: Keep a wheelbarrow nearby – there is going to be a lot of soil coming out. Alternatively, lay a sheet of plastic alongside the trench (this in particular helps if you are trying to preserve a nice lawn) and stack the soil on top of that (remember that there still will be excess soil to get rid of, once the pipe is laid in the trench).
Step 3: Add a Base Layer of Gravel
Line the bottom of the trench with coarse gravel (around 5-10cm deep). This gives water a place to flow before it enters the pipe. Use angular gravel, not round pea shingle, so it locks in place.
Step 4: Lay the Geotextile / Landscape Fabric
Line the trench with landscape fabric, letting the edges overlap the sides. This stops soil clogging the drain but still lets water pass through.
Step 5: Add the Perforated Pipe
Place your drainage pipe on top of the gravel. The holes should face downwards – this surprises some people, but it actually helps water enter the pipe more efficiently.
Step 6: Cover the Pipe with More Gravel
Pour more gravel over the pipe until it’s about 5-10cm from the top of the trench.
Step 7: Fold Over the Fabric
Wrap the landscape fabric over the top of the gravel creating a covered top to the trench (see the blue line in the picture). This adds another layer of protection from soil and roots.
Step 8: Finish with Topsoil or Decorative Stone
You can now cover the trench with soil, turf, bark, or decorative pebbles – depending on the look you’re after.
Even though it’s a fairly straightforward job, a few common errors can stop your French drain from doing its thing:
| Item | Estimated Cost (UK) |
|---|---|
| Perforated drainage pipe (10m) | £25–£40 |
| Gravel (bulk bag) | £50–£75 |
| Geotextile fabric | £30–£60 |
| Tool hire (optional) | £20–£50 |
| Misc. (gloves, barrow, etc.) | £10–£30 |
| Total | £150–£300 |
For a 5-10m French drain, expect a weekend job. Hard ground, roots, or awkward layouts may take longer.
Professionally installed French drains for domestic gardens usually cost between £750 and £1,500, depending on length, access, and complexity.
If you value time, don’t want the hassle of digging, or the issue is widespread – yes. It guarantees proper grading, waste removal, and peace of mind.
DIY is great – but sometimes drainage needs more than just elbow grease and hard labour. Here are a few times when it’s worth getting the experts involved:
At PM247, we’re on hand to provide a professional assessment and carry out French drain installations safely and efficiently. We know exactly how to tailor drainage solutions to your property, whether it’s a small garden fix or part of a larger landscaping job.
Here’s what our customers say:
Call us now on 08082 504 203, or book online – we’re here to help keep your home and garden in fully functional order.
A French drain can be a total game-changer for your garden. It’s not the flashiest upgrade, its purely functional and practical, but when it comes to protecting your home from water damage and keeping your lawn usable year-round, it’s a very smart solution.
If you’re confident with a shovel, feeling strong and up for a weekend project, follow the steps above and give it a go. But if you’d rather skip the guesswork and get it done right first time, contact our friendly team and we’ll be around in no time at all.
At PM247, we’re here 247 – not just for blocked drains and plumbing emergencies, but for smart, long-lasting drainage solutions too. Whether you’re just after advice or ready to book an installation, or you can call us now on 08082 504 203.
Yes – they’re one of the most reliable garden drainage solutions when installed properly.
Typically 45-60cm deep is enough for most garden setups. Just make sure the slope is consistent.
Not usually. But if you’re connecting it to public drainage or near boundaries, check with your local authority.
The holes need to point down. This allows water to seep in from below and helps prevent blockages.
Yes. Once installed and covered with soil, you can turf it, and your garden will look untouched.
They can last 20-30 years if installed correctly with proper materials and minimal soil ingress.
You can, but it’s not ideal. Wet conditions make digging harder and can ruin your grading, likewise very dry weather makes the digging very hard too.
