The right garden drainage solution depends on why the water is sitting there. Compacted or heavy clay soil is improved by aerating it and working in organic matter, a lawn that stays wet all winter usually needs a French drain or land drains running to a soakaway, and a wet patch that never dries, even in a dry spell, is often a broken drain or a leaking pipe rather than the soil.

Why your garden is waterlogged

Water sits on a garden when it arrives faster than the ground can take it away. That comes down to one of a handful of causes, and each one has a different fix. Spending time on the cause first saves digging a drain that does not solve the problem.

Cause	What you might notice	Usual fix	Who does it
Compacted soil	Puddles after rain that clear within a day or two, moss, thin grass on paths and play areas	Aerate, spike or hollow tine the lawn, add organic matter to beds	Usually DIY
Heavy clay soil	Ground wet and sticky all winter, cracks in summer	Soil improvement, raised beds, land drains	DIY or landscaper
High water table or a low spot	Water sits in the same hollow every winter, test hole fills from below	French drain or land drains to an outfall, regrading	Landscaper or groundworker
Run-off from hard surfaces	Water pours off a patio, driveway or a neighbour’s higher ground	Channel drain, redirecting water to a soakaway, permeable paving	Drainage engineer or landscaper
Downpipe or failed soakaway	Wet ground near a downpipe, gutters overflowing, the area stays wet long after rain	Clear or rebuild the soakaway, reconnect the downpipe	Drainage engineer
Broken drain or leaking water pipe	A wet patch in dry weather, a sewage smell, sinking ground, a rising water bill	CCTV survey or leak detection, then repair	Drainage engineer or plumber

Clay soils are common in parts of Hertfordshire and Bedfordshire, and a lot of new build gardens sit on subsoil that was compacted by machinery during building, with a thin layer of topsoil on top. Both drain slowly. Where the cause is a pipe, a gully or a soakaway rather than the soil, it is a job for our drainage services team.

Test the ground before you dig

The Royal Horticultural Society suggests a simple test. Dig a hole 30 to 60cm deep, fill it with water and cover it so rain cannot get in. If the water is still there hours later, or even days later, the soil would benefit from drainage.

Do it in a few places, and do it at a wet time of year. Watch where the water comes from, too. If the hole fills up from below without you adding anything, the water table is high and surface treatments will not help much.

It is also worth ruling out a leak. Turn off every tap and appliance and watch your water meter. If it keeps moving, water is escaping somewhere, and a leaking underground supply pipe can keep a patch of lawn soaked all year round. Our leak detection service can find it without digging up the whole garden.

Garden drainage solutions compared

Solution	Best for	How it works	DIY or professional
Aeration and soil improvement	Compacted lawns and beds	Spiking or hollow tining opens the surface, and organic matter improves structure over time	DIY
Raised beds or planting for wet ground	Areas with no outfall	Lifts roots above the wet layer, or uses plants that like damp soil	DIY
French drain	A wet strip, the bottom of a slope, along a path or wall	A gravel-filled trench, often with a perforated pipe, collects water and carries it away	DIY for short runs, otherwise professional
Land drains in a herringbone layout	Whole lawns that stay waterlogged	Perforated pipes in gravel feed a main drain that runs to an outfall	Professional
Channel drain	The edge of a patio or driveway	A grated channel catches surface water and pipes it to a soakaway or drain	Professional
Soakaway	Where the water needs to go	A pit or crate system in the ground lets collected water soak away slowly	Professional

French drains

A French drain is a trench filled with coarse gravel, topped with a permeable membrane or upturned turf and then topsoil. Most now include a perforated pipe in the gravel so water moves faster. It needs a steady fall along its length and an outlet at the low end. Without the outlet, it simply fills up.

Land drains

For a whole lawn, the RHS describes a herringbone pattern, with branch drains meeting the main drain at 45 degrees. Its guidance is to lay pipes 40 to 60cm deep and 3 to 6m apart, at a fall of about 1 in 40 towards the outlet, on 5cm of gravel with 10cm of gravel over the top. The driest part of the year, late summer into early winter, is the easiest time to do it.

Where the water goes

Every drainage solution moves water from one place to another, so the most important question is where it ends up.

For rainwater, the Building Regulations set an order of priority: an adequate soakaway or other infiltration system first, a watercourse if that is not reasonably practicable, and a sewer only as a last resort. The RHS notes that local byelaws usually prohibit adding garden drainage water to sewers or storm drains, so connecting land drains into your household drains is normally not allowed without the water company’s agreement.

A soakaway has to be sized for the area it serves and the soil it sits in, which is why a percolation test comes first. Building Regulations guidance says a soakaway should not generally be built within 5 metres of a building or a road. On heavy clay, a soakaway may barely drain at all, which is where some DIY projects come unstuck. And do not direct water onto a neighbour’s land.

If you are paving a front garden, the Planning Portal says you need planning permission for more than five square metres of traditional impermeable surface unless the water runs to a lawn or border to drain naturally. Permeable surfaces such as gravel or permeable block paving do not need it.

When the problem is a drain, not the soil

Some waterlogged gardens have nothing to do with soil or rainfall. A cracked or collapsed drain, a blocked gully, a soakaway that has silted up, or a leaking water supply pipe can all put water into the ground, often in the same spot, whatever the weather.

Signs that point to a pipe fault rather than the soil:

• the wet patch stays wet during a dry spell
• it appeared suddenly in a garden that used to drain well
• there is a smell of sewage, or grass is unusually lush in one strip
• drains inside the house are slow or gurgling
• paving or lawn is sinking along a line

This is where a drainage engineer comes in. A CCTV drain survey shows the inside of the pipe on camera, so we can see cracks, displaced joints, root ingress and collapses without digging, and you get the footage and a report. Where there is damage, drain repairs or lining put it right. Our guide to when you need a CCTV survey explains more, and if you are not sure whose pipe it is, read who is responsible for a drain.

What it costs with Vantage

In normal working hours there is no call-out fee. After the first hour, time is charged in half-hour steps, and parts are quoted before we fit them. Evening, weekend and overnight visits are charged at the out-of-hours rates. Every rate is published on our prices page, so you know what you will pay before we arrive. Larger drain repairs are quoted before any work starts.

Clearing a blocked gully or soakaway inlet is at the simpler end. Excavating and rebuilding a soakaway, or repairing a collapsed section of drain, costs more because of the digging involved. Our drainage work carries a 12 month labour guarantee.

Frequently asked questions

What is the best drainage for a waterlogged lawn?

Start with aeration and organic matter, because most waterlogged lawns are compacted rather than badly drained. If the lawn still sits wet through winter after that, land drains in a herringbone pattern running to a soakaway are the usual long-term fix.

How deep should a French drain be?

It depends on the soil and what you are draining. The RHS guidance for land drains is 40 to 60cm deep with a fall of about 1 in 40, and French drains are often dug to a similar depth. What matters most is a steady fall and a working outlet at the low end.

Can I connect garden drainage to my house drains?

Normally no. Land drainage should go to a soakaway or watercourse, and byelaws usually stop garden drainage water going into the public sewer. Connecting it to a foul drain can overload the system and cause flooding elsewhere.

Why is one part of my garden always wet, even in summer?

Ground that stays wet in dry weather usually has water arriving from a pipe, not from rain. A leaking water supply pipe, a broken drain or a failed soakaway are the most likely causes, and a CCTV survey or leak detection will find it.

Do I need planning permission for garden drainage?

Laying land drains in a back garden does not normally need planning permission. Paving more than five square metres of a front garden with an impermeable surface does, unless the water drains to a lawn or border, and you should check with your council if you live in a conservation area.

Help in Hertfordshire, Bedfordshire and Cambridgeshire

If your garden has started holding water and you suspect a broken drain, a failed soakaway or a leaking pipe, our engineers can survey it, show you the footage and put it right. See our drainage services or call 01462 506374, answered 24 hours a day, 7 days a week.