When water stands in the lawn after every downpour, when damp presses against the cellar wall or the driveway drains onto next door's plot, waiting will not help: without drainage that works, the fabric of the building, the planting and the surfaces all suffer. Gala Bau Kurt plans and builds land drainage (Drainage), channel drains, soakaway chambers and soakaway crate systems for private plots, apartment buildings and commercial sites in Düsseldorf, Wuppertal, Schwelm, Ennepetal, Meerbusch, Cologne and throughout North Rhine-Westphalia.
We begin by establishing where the water is coming from and where it can go – soil type, fall, groundwater level and the sewer connection decide the solution. After that you receive a fixed-price quote; excavation, materials, backfilling and disposal all come from one firm, and we are happy to talk the whole scheme through with you in English as well as German and Turkish.
What we do in drainage and rainwater management
From a channel drain along the patio to a perimeter drain around the house – we build what your plot actually needs.
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Laying land drainage in the garden
Perforated DN 100 land drains bedded in gravel and wrapped in geotextile, to stop waterlogging in lawns and beds.
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Perimeter drainage around the house
A drain along the cellar wall to DIN 4095 with a gravel filter surround, rodding chambers and a controlled outfall.
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Installing channel drains
Linear drainage in front of garages, patios and cellar steps, set in concrete, with the load class to DIN EN 1433.
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Soakaway chambers & soakaway crates
Letting roof and yard water soak away on site – a gravel trench, plastic soakaway crates or a chamber with a silt trap.
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Yard drainage & paved surfaces
Falls, channels, yard gullies and permeable paving, so that the drive and the yard stay dry in heavy rain.
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Patio drainage
A box channel along the façade, the correct fall and a drainage mat beneath the slabs – no standing water at the house wall.
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Curing a waterlogged lawn
Subsoiling, sand slits and perforated drain runs – whichever combination suits your soil, against moss and puddles.
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Refurbishing existing drainage
Locating silted-up runs, jetting them clean, retrofitting inspection chambers or renewing individual sections.
How we build a drain that goes on working
A drain is only as good as its build-up. Depending on the job we dig the trench 60 to 100 cm deep – against a building down below the level of the cellar floor slab – and line it with geotextile. On top of that go a levelling layer of 8/16 or 16/32 gravel and the DN 100 land drain (fully or partially perforated), laid to a fall of at least 0.5 % towards the outfall. The trench is backfilled with filter gravel, closed over the top with geotextile and only then covered with soil, turf or a hard surface.
At changes of direction and at the low point we install rodding chambers (Spülschächte) so that the run can be jetted and maintained later on. The outfall leads into a soakaway chamber, a soakaway crate system or the surface water sewer; where there is no fall to be had, it goes via a pumping chamber. For drainage against a building we work to DIN 4095 – bearing in mind that a drain takes the load off the structural waterproofing but never replaces it.
Channels, soakaway crates and soakaway chambers – getting rainwater away properly
On yards, driveways and patios, surface water has to disappear quickly when it rains hard. We set channel drains into a C25/30 concrete bed with a haunch on both sides and choose the load class to suit the use: A 15 for footpaths, B 125 for car parking spaces, C 250 for driveways. Paved surfaces are laid to a fall of 2 to 2.5 % away from the building; wherever it is feasible, we plan permeable paving with open joints and a free-draining sub-base.
If rainwater is to soak away, we first check how permeable the ground is (the kf value) and how high the groundwater stands. Plastic soakaway crates store roughly three times as much water as a gravel trench of the same size; like a soakaway chamber built from concrete rings, they are wrapped in geotextile and given a silt trap upstream. We size them to DWA-A 138 and, as a rule, keep at least 6 m clear of the building. If your patio or a flight of cellar steps lies below the street's backflow level (Rückstauebene), an anti-flood valve belongs in the scheme as well.
Drainage in Wuppertal, Düsseldorf, Cologne & NRW: clay, sand and groundwater
In the Bergisches Land – Wuppertal, Schwelm, Ennepetal, Gevelsberg, Remscheid – 1,100 to 1,200 mm of rain a year falls on shallow, stony, often clayey soils over slate and greywacke. Very little of it soaks away here, so the task is to intercept hillside water before it reaches retaining walls, patios or the cellar wall: cut-off drains above the house, drainage behind retaining walls, and perforated drain runs against waterlogging in the lawn.
On the Rhine plain around Düsseldorf, Meerbusch, Neuss and Cologne, the loamy sands of the lower terrace drain freely – ideal for soakaway crates and soakaway chambers, which let you disconnect roof water from the sewer and reduce the surface water charge (Niederschlagswassergebühr). Take care close to the Rhine, though: in Kaiserswerth, Wittlaer, Urdenbach, Nierst or Rodenkirchen the groundwater stands high, so a soakaway crate has no room left to discharge into. In those cases we plan shallow infiltration basins, storage with a throttled outlet, or a connection into the sewer instead. From the Ennepe-Ruhr-Kreis we are with you in 15 to 70 minutes via the A1, A46 and A43.
- Wuppertal, Schwelm & Ennepetal: hillside water, clay soils, drainage behind retaining walls
- Düsseldorf & Meerbusch: infiltration into sandy soils, with an eye on groundwater near the Rhine
- Cologne: courtyards, yard drainage, disconnecting roof areas from the sewer
Permits, the sewer connection and the tax allowance
Letting rainwater soak away on site is very much wanted in NRW, but in water law it counts as a use of a body of water. Whether a permit from the lower water authority (Untere Wasserbehörde) is needed depends on where the water comes from (roof or yard), on the size of the area and on the location – in a water protection zone, for example. Changes to the sewer connection – a new yard gully, or disconnecting roof areas – have to be notified to the municipal drainage authority (Stadtentwässerungsbetrieb). We check what your local authority requires beforehand and, if you wish, handle the correspondence for you.
Drainage and earthworks go particularly well from autumn through to spring, while the ground is frost-free and lawns and beds are dormant. For an existing home there is one more point worth knowing: 20 % of the labour costs – up to €1,200 a year – can be set against your income tax as a tradesman's service under § 35a of the German Income Tax Act (§ 35a EStG); we show labour, travel and machine costs separately on the invoice.
How we go about your drainage project
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Site visit & finding the cause
We look at the wet spots, the falls, the soil, the downpipes and any existing chambers – free of charge, and gladly with your photos from the last downpour sent over in advance.
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Scheme & fixed price
A proposal covering the pipe runs, where the water will finally go and the materials, plus a fixed-price quote including excavation and disposal.
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Excavation & installation
With a mini digger or by hand we dig out the trenches, lay pipes, channels and chambers, and check the fall as we go.
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Backfilling & handover
Backfilling in layers, reinstating lawn or paving and carting the spoil away – together with a sketch showing where the pipes and chambers run.
What does a drainage system cost?
Length, depth, soil, access and the point where the water can finally go are what decide the price. Non-binding guide figures incl. VAT:
| Scope of work | Costs & Prices |
|---|---|
| Land drain in the garden (simple perforated run) | approx. €50–100 per linear metre |
| Complete drain (trench, gravel, geotextile, pipe, backfill) | approx. €100–150 per linear metre |
| Perimeter drain around the house (deep dig, chambers) | approx. €150–250 per linear metre |
| Channel drain incl. concrete bed and grating | approx. €100–300 per linear metre |
| Soakaway crate system in plastic (material per m³) | from approx. €100–200 per m³ |
| Mini digger incl. operator | approx. €65–100 per hour |
Rodding chambers, a pumping chamber or an anti-flood valve are costed separately as required. You receive a binding fixed-price quote after the free on-site visit.
All figures are non-binding guide prices incl. VAT. The final price depends on area, access, materials and effort. You will receive a binding fixed-price quote after a free on-site visit.
Frequently Asked Questions
What does it cost to have drainage laid?
A simple perforated drain run in the garden works out at roughly €50–100 per linear metre, a complete drainage trench at €100–150, and a perimeter drain around the house at €150–250 (incl. VAT). On top of that come the chambers and the outfall itself. After the free on-site visit we give you a fixed price.
How deep does a garden drain have to be?
For lawns and beds we normally lay perforated runs 60–80 cm deep, spaced about 5–10 m apart depending on the soil. Against a building, the drain has to sit below the level of the cellar floor slab. In every case it needs a fall of at least 0.5 % and an outfall that actually works.
What helps against a waterlogged lawn?
First establish the cause: compacted soil, a clay subsoil or the lack of an outfall. Where compaction is the problem, hollow-tine aeration, subsoiling and top-dressing with sand help; on heavy soils you need perforated drain runs connected to a soakaway chamber or the sewer. We often combine the two and oversow the lawn afterwards.
Am I allowed simply to let rainwater soak away in my garden?
For roof water from a house that is frequently unproblematic; for yards, parking areas, water protection zones or a high groundwater table, a permit from the lower water authority (Untere Wasserbehörde) may be required. Changes to the sewer connection have to be notified to the municipal drainage authority (Stadtentwässerungsbetrieb) – we clarify all of this with you in advance.
Soakaway crates or a soakaway chamber – which is better?
A soakaway chamber takes up little space, but it only works where the subsoil is permeable and there is enough clearance to the groundwater. A crate system spreads the water over a wider area, stores more of it and also fits under a lawn or a driveway. On the clay soils of the Bergisches Land, what often remains is a crate system with a throttled outlet, or a connection into the sewer.
Can I claim drainage work against my tax?
Yes – for an existing home (not a new build), drainage counts as a tradesman's service under § 35a of the German Income Tax Act (§ 35a EStG): 20 % of the labour, travel and machine costs, up to a maximum of €1,200 a year, comes straight off your tax bill. You need an invoice showing the labour costs separately, and payment by bank transfer rather than in cash.