Groundworks & Water Management
Drainage & Groundworks in Birmingham
Soakaways, channel drains, sub-bases and level changes across Birmingham and the surrounding areas. The part of a landscaping job you never see, and the part that decides whether the rest of it lasts.
Standing Water Is A Symptom, Not The Problem
A lawn that turns to mud every October, a patio with a puddle that never quite dries, a garage floor that floods in a downpour: these are rarely fixed by the thing people try first. Sanding a lawn, drilling holes in paving or adding a bit more fall at the edge treats the surface. If the water has nowhere legitimate to go, it will simply find the next lowest point.
We start underneath. That means finding out what the ground is actually made of, where the existing surface water drainage runs, whether infiltration is realistic on your plot, and what the finished levels need to be. With over 20 years of experience in groundworks across Birmingham we have dug enough trial holes to know that two gardens on the same street can behave completely differently, and that a made-up level from a 1960s build will not perform like undisturbed subsoil.
Solve It Underground
Channel & Linear Drains
Slot and grated channel run along the low edge of paving and connected to a proper outfall.
Soakaways
Sized from a percolation test, set the correct distance from buildings, and backfilled to stay open.
Land Drainage
Perforated pipe in a permeable trench to intercept water before it reaches the lawn or patio.
Sub-Bases & Formation
Dug to depth, laid in layers and compacted, so the surface above has something to sit on.
Level Changes & Excavation
Cutting and filling to create usable terraces, with retention and drainage designed together.
Gullies & Connections
New gullies, catchpits and rodding access tied into the existing surface water system.
The Groundworks Are The Job
Most of what goes wrong in a garden traces back to something buried. Paving drops because the sub-base was too thin or was never compacted. A retaining wall bows because there is no drainage behind it and the ground behind it is saturated. A new lawn dies because the topsoil was spread over a compacted crust the machinery left behind. None of that shows up in a photograph on the day, and all of it shows up two winters later. We would rather be judged on what is under the surface.
The Rules That Decide The Design
Rainwater Has A Legal Route, Not Just A Downhill One
Garden drainage is one of the few parts of landscaping with a genuine rulebook behind it, and it is worth knowing what it says before anyone starts digging. Where surface water is allowed to go, who has to agree to it, and what needs a formal consent are all fixed points. They change what a scheme costs, so we settle them at the survey rather than halfway through.
What applies to your garden depends on your ground conditions, your existing drainage and your property, so read the below as the checklist we work through on site rather than a conclusion about your address.
The Part H hierarchy comes first
Approved Document H of the Building Regulations sets the order for rainwater disposal: infiltration into the ground where it is reasonably practicable, then a watercourse, then a sewer. It is a hierarchy, not a menu. Surface water should not be put into a foul sewer where an alternative exists, and doing so can overload the system and cause problems downstream. On a plot where infiltration genuinely will not work, that has to be demonstrated rather than assumed, which is what the trial hole and percolation test are for.
Soakaway design, not soakaway guesswork
A soakaway is sized from a measured percolation rate using the BRE Digest 365 method, not from the size of the patio. It is normally kept at least five metres from a building so that discharge is not softening the ground under foundations, and clear of boundaries, drains and tree root protection areas. Birmingham ground varies a lot: free draining sand and gravel in some areas, heavy clay or made ground in others. On clay, a soakaway can fill faster than it empties, and a different solution is the honest answer.
Connections and consents around Birmingham
Severn Trent Water is the water and sewerage undertaker for Birmingham, and a new connection to a public sewer is made with the undertaker's approval under section 106 of the Water Industry Act 1991. If the proposal is to discharge into an ordinary watercourse, ditch or culvert instead, that normally needs land drainage consent from the lead local flood authority under the Land Drainage Act 1991. Birmingham City Council is the lead local flood authority for the city. These are not obstacles, but they are not things to discover after the trench is open.
What sits above the drainage matters too
Groundworks rarely stop at the pipe. A retaining structure holding a new level needs drainage behind it and weep holes or a drain run to relieve water pressure, or it will move. Paving is kept at least 150mm below the damp proof course with the fall running away from the house. Excavation close to a neighbouring wall or foundation can bring the Party Wall etc. Act 1996 into play. If there are protected trees on or near the plot, a tree preservation order or conservation area status means works near roots need notice to the council first.
This sets out the rules that commonly apply in England and what we check on site. It is not advice on your specific property. Where a scheme needs a percolation test, a sewer connection application or a land drainage consent, we will tell you at quoting stage and price it in.
Why Call Us For A Wet Garden
Plenty of landscapers will lay a lovely patio. Fewer will tell you the reason your last one failed is that the water had nowhere to go, and fewer still will dig a hole to prove it before quoting.
20+ Years of Groundworks
Excavation, sub-bases and drainage across Birmingham gardens and driveways.
We Test Before We Price
Trial hole and percolation where it matters, rather than assuming the ground will take it.
Designed To An Outfall
Every run ends somewhere legitimate, with rodding access so it can be maintained.
One Team Start To Finish
The groundworks crew and the landscaping crew are the same people, so nothing gets lost between trades.
What Our Clients Say
What Else We Do
Our Services
Patios & PavingPorcelain, sandstone and block paving laid on a proper base with the falls worked out first.View service 
Garden Design & LandscapingFull garden makeovers that set levels, drainage and planting out as one plan rather than piecemeal.View service 
Turfing & Artificial GrassNatural turf and artificial grass laid over a free draining base so the surface stays usable.View service 
Garden Walls & BrickworkRetaining walls, sleeper terraces, steps and brick edging built to hold ground and shed water.View service 
Driveways & SurfacingBlock paving, tarmac, gravel and resin bound driveways installed across Birmingham.View service 
Fencing & DeckingClose board and panel fencing, gates and timber decking built to last a Birmingham winter.View service 
Get A Wet Garden Looked At
Questions & Answers
Why does my garden flood every winter?
Usually one of three things. The ground is heavy clay or compacted made ground and simply will not take water quickly. The garden falls towards the house or towards a low point with no outlet. Or an existing gully, channel or land drain has silted up and stopped working. The first job is to establish which, because the fix is completely different in each case.
What is a percolation test and do I need one?
It is a measured test of how fast water soaks away into your ground. A pit is dug, filled with water and the drop in level is timed, repeated for consistency, and the result feeds into the soakaway sizing under BRE Digest 365. You need one if a soakaway is being proposed. Without it, a soakaway is a guess, and an undersized one simply fills up and backs out at the surface.
Can I connect my patio drainage into the foul drain?
It should be avoided. The Part H hierarchy puts infiltration first, then a watercourse, then a sewer, and surface water going into a foul sewer adds volume the system was not designed for. If a sewer connection is the only realistic option, it is made with the sewerage undertaker's agreement, which for Birmingham is Severn Trent Water, under section 106 of the Water Industry Act 1991.
How far from the house does a soakaway have to be?
Guidance in Approved Document H puts a soakaway at least five metres from a building, so that the water being discharged is not softening the ground supporting foundations. It also wants to sit clear of boundaries and other drainage. On a small urban plot that distance is often the constraint that rules a soakaway out, which is worth knowing before the design is settled.
Will a French drain fix my lawn?
Sometimes, and it depends entirely on where the water is coming from. A land drain intercepting water running in from a higher neighbouring level can transform a lawn. The same drain in a flat clay garden with nowhere to discharge to will just become a wet trench. The question is never whether to install a drain, it is where the water in it is going to go.
Do I need permission to add a channel drain?
Installing the channel itself is not usually the issue. The consent question attaches to the outfall: a new connection to a public sewer needs the undertaker's approval, and a discharge into an ordinary watercourse normally needs land drainage consent from the lead local flood authority, which is Birmingham City Council within the city. If we are connecting into an existing surface water gully on your own property, that is generally straightforward.
How deep should a sub-base be?
It depends on the loading and the ground. A domestic patio on sound subsoil needs considerably less than a driveway carrying a car, and soft or made ground needs more again, sometimes with a geotextile separator to stop the sub-base disappearing into it. What matters as much as depth is that it is laid and compacted in layers rather than tipped in one go, because a thick uncompacted layer will settle unevenly.
Can you work around a manhole or inspection chamber?
Yes. Chambers need to stay accessible, so we either work the levels around the existing cover or fit a recessed tray cover that takes the paving and keeps the chamber openable. What we will not do is pave over an inspection chamber. Losing access to a drain is the kind of shortcut that costs far more the first time something blocks.
Is my garden in a flood risk area?
That is a question for the flood maps rather than a landscaper's opinion, and parts of Birmingham sit within the River Rea and River Tame catchments. What we can say is that surface water flooding in a garden is very often a local drainage problem rather than a river one, and it is usually solvable on the plot. If a scheme looks like it needs a formal flood risk view, we will say so.
How much does garden drainage cost?
It is driven by the outfall, not the length of pipe. A channel drain tied into a gully a few metres away is a modest job. A soakaway that needs a percolation test, a large excavation and crate storage is a different order. That is why we survey and test first and then price a defined scheme. Call 07837 577358 and describe where the water is sitting, and we will tell you what we would need to look at.
Stop Guessing Why The Water Sits There
Tell us where the puddle forms and how long it stays. We will come and look at the levels, dig a trial hole where it is worth it, and set out what the drainage actually needs to do before anyone talks about paving.