Clark Drainage provides professional soakaway installation services for residential and commercial properties across the UK.
Water pooling on your lawn after every rainfall. A patio that floods whenever it rains. Gutters overflowing even though they’re clear. These are signs your property’s drainage isn’t working properly, and a soakaway could be the solution.
We install new soakaways, replace failed systems, and connect surface water drainage to get water off your property and into the ground where it belongs. Every installation is designed to meet Building Regulations and signed off by Building Control.
What is a soakaway?
A soakaway is an underground structure that collects rainwater and allows it to drain slowly into the surrounding soil. Instead of water sitting on the surface or overloading the public sewer system, it disperses naturally into the ground.
The basic principle is simple. Rainwater from your roof, driveway, or patio flows through drainage pipes into the soakaway. The soakaway holds the water temporarily while it percolates into the earth. Over time, the water filters down through the soil and rejoins the natural water table.
Modern soakaways use plastic crate systems wrapped in geotextile membrane. These crates are strong, lightweight, and provide more storage capacity than traditional rubble-filled pits. They’re quicker to install and last longer too.
Signs you need a new soakaway
Soakaways don’t last forever. Older systems filled with rubble gradually clog with silt and debris. The surrounding soil can become compacted or waterlogged. Tree roots grow into the drainage and block it. When a soakaway fails, the problems are usually obvious.
Waterlogging and pooling
If water sits on your lawn for hours or days after rain, your soakaway isn’t draining properly. The ground around the soakaway may feel permanently boggy, even in dry weather. This standing water damages your lawn and creates ideal conditions for moss.
Overflowing gutters and drains
When downpipes connect to a blocked soakaway, water has nowhere to go. You’ll see gutters overflowing even though they’re clean, and water backing up through gully drains. The water finds other routes, often along walls and into foundations.
Flooding and erosion
Serious soakaway failure causes surface flooding that washes away topsoil and damages planted areas. If water is running across your property rather than draining into the ground, your drainage system needs attention.
Damp and subsidence
Water that can’t drain away properly can affect your building. Persistent damp on external walls, wet patches in cellars, or even early signs of subsidence can all trace back to failed drainage. These problems get worse and more expensive to fix the longer you leave them.
When soakaway installation is required
You might need a soakaway installed for several reasons beyond replacing a failed system.
New builds and extensions
Building Regulations require that surface water from new buildings is managed on site wherever possible. If you’re building an extension, garage, or new property, you’ll likely need a soakaway to handle the additional roof runoff. Your plans will need to show how surface water is being dealt with before Building Control signs off.
New driveways and paving
If you’re paving over more than five square metres of your front garden, planning rules require that surface water drains into a permeable surface or a soakaway. You can’t just let it run into the road or public drain. A soakaway solves this problem.
Improving existing drainage
Some properties were built without proper surface water drainage, especially older homes. Water from roofs might discharge onto the ground near foundations, causing damp problems. Installing a soakaway and connecting your downpipes gives the water somewhere proper to go.
The soakaway installation process
Every soakaway installation starts with understanding your site. We don’t just dig a hole and drop in some crates. The system needs to be designed for your specific conditions, and it needs to meet Building Regulations.
Step 1: Site survey
We visit your property to assess the drainage problem, identify the best location for the soakaway, and check for any complications. We look at where the water is coming from, what space is available, and how we’ll access the site. This survey is free and comes with no obligation.
Step 2: Percolation test
Before designing your soakaway, we need to know how quickly your soil absorbs water. We dig a test hole, fill it with water, and measure how fast it drains. This percolation test tells us what size soakaway you need and whether a soakaway will work at all in your ground conditions.
If the percolation test shows your soil drains too slowly (often the case with heavy clay), we’ll discuss alternative options. There’s no point installing a soakaway that won’t function properly.
Step 3: Design and quote
Based on the survey and percolation test, we design a soakaway system sized for your property. We calculate the volume needed based on the roof area draining into it and the percolation rate of your soil. You receive a fixed quote covering excavation, materials, installation, and connection to your existing drainage.
Step 4: Excavation
We excavate the pit for your soakaway at the required depth and dimensions. All the spoil is removed from site. If we’re installing under a lawn, we carefully set aside the turf for replacement afterwards. For driveway installations, we remove the surface and sub-base as needed.
Step 5: Installation
The soakaway crates are assembled and wrapped in geotextile membrane, which prevents silt from clogging the system while allowing water through. The crates are placed in the excavation and connected to your drainage pipes. We backfill around the system and compact the ground properly.
Step 6: Reinstatement
We put your garden or driveway back together. Turf is relaid, soil is levelled, or paving is replaced depending on the location. We leave the site clean and tidy, with your new drainage system ready to use.
Soakaway installation costs
The cost of installing a soakaway depends on the size of system you need and how easy your site is to access. Here are typical price ranges.
By soakaway size
A small soakaway (around 200 litres) suitable for a single downpipe costs £500 to £650. A medium system (400 to 800 litres) handling multiple downpipes runs £800 to £1,100. Larger installations using multiple crates for bigger properties cost £1,500 to £2,500.
By location
Installing under a lawn is simpler and cheaper than under a driveway. Lawn installations typically cost £600 to £900, while driveway installations requiring surface removal and replacement cost £1,000 to £1,500 or more.
Additional costs to consider
Percolation testing costs £150 to £300 if not included in your quote. Building Control approval adds £200 to £400. Muck away charges for removing the excavated soil are usually included, but check your quote. Reinstating turf or reseeding costs extra if the ground needs levelling.
We provide fully itemised quotes so you know exactly what’s included. The price we quote is the price you pay, with no hidden charges.
Soakaway regulations UK
Soakaway installation is covered by Building Regulations, and you need to follow the rules to get your system signed off.
Distance requirements
A rainwater soakaway must be at least five metres from any building. If the ground slopes toward the building, you need more distance. The soakaway should be at least 2.5 metres from your property boundary and at least 10 metres from any watercourse.
Building Control approval
New soakaways connected to building drainage need Building Control sign-off. This applies to new builds, extensions, and replacement systems. The Building Control officer will want to see your percolation test results and soakaway design before approving the installation.
Percolation test requirements
Building Regulations require a percolation test to prove the ground is suitable. This isn’t optional. Without test results showing adequate drainage, Building Control won’t approve your system. The test method is defined in BRE Digest 365.
Foul water restrictions
Soakaways can only handle clean rainwater. They cannot receive foul water from toilets, sinks, or washing machines. If you need to deal with foul drainage, you need a septic tank with a drainage field, which is a different system with different regulations.
Types of soakaway systems
There are two main types of soakaway, and modern installations almost always use crate systems.
Crate systems
Plastic soakaway crates are modular units that lock together to create the required storage volume. They’re wrapped in geotextile membrane and buried in the ground. Crates provide 95% void space, meaning almost all their volume is available for water storage. They’re lightweight, quick to install, and last for decades.
Rubble-filled pits
Traditional soakaways were pits filled with rubble, broken bricks, or gravel. These systems only provide about 30% void space, so they need to be much larger to store the same amount of water. They also silt up over time as debris washes in and settles between the rubble. We don’t install rubble soakaways because crate systems perform better and last longer.
Why choose Clark Drainage for soakaway installation
We’ve been installing drainage systems since 2005 and understand what it takes to get the job done properly.
Full service from survey to sign-off
We handle everything: site survey, percolation testing, design, installation, and liaison with Building Control. You deal with one company from start to finish, not multiple contractors.
Nationwide coverage
With offices across the UK, we can reach most properties quickly. Check our local service centres to find your nearest team.
Fixed pricing
We quote a fixed price after surveying your property. That price includes everything we discussed. No surprises, no hidden extras. If we find something unexpected during the work, we discuss it with you before proceeding.
Proper documentation
You receive full documentation for your soakaway installation, including percolation test results, design calculations, and Building Control approval. This is important if you ever sell your property or need to demonstrate compliance.
Frequently asked questions
How long does soakaway installation take?
Most residential soakaways take one to two days to install. Larger systems or difficult access can extend this to three days. We’ll give you a clear timeframe when we quote.
Do I need planning permission?
Soakaways for surface water drainage don’t usually need planning permission. Building Regulations approval is separate and is required for most installations. We handle the Building Control process for you.
How far should a soakaway be from my house?
At least five metres for rainwater soakaways. If your property is on a slope, the soakaway should be on the downhill side and may need to be further away to prevent water affecting your foundations.
Can I install a soakaway myself?
You can, but you’ll still need to meet Building Regulations. That means conducting a proper percolation test, designing the system correctly, and getting Building Control sign-off. Most people find it easier to use a professional who handles all of this.
Will a soakaway work in clay soil?
It depends. Heavy clay drains very slowly, and a percolation test may show it’s unsuitable for a soakaway. If that’s the case, you’ll need alternative drainage such as connecting to a surface water sewer (with water authority permission) or an attenuation system.
What size soakaway do I need?
The size depends on the roof area draining into it and your soil’s percolation rate. A small garage might need a 200-litre soakaway. A whole house could need 1,000 litres or more. We calculate the correct size during the design stage.
Book your free site survey
If you’re having drainage problems or need a soakaway for a building project, we can help. Call us on 0141 280 3431 or fill in the form below to arrange a free site survey.
We’ll assess your property, conduct a percolation test if needed, and provide a fixed-price quote for the complete installation.
Available 24/7 for emergency drainage problems. Standard surveys booked within 48 hours.
