Excavation dewatering · wellpoint pumps · since 1988
We carry out complete dewatering works on construction sites — from choosing the method, through installing the system, to running it for as long as the works last.
Dewatering an excavation means removing groundwater and rainwater from the working area and holding the water table below the excavation floor. Without it the floor turns to slurry, the slopes lose stability, and concreting or pipe laying has to stop. A well-designed dewatering scheme is usually not an extra cost — it shortens the build and removes standstills.
We dewater excavations for gas pipelines, sanitary sewers, separators, pumping stations, pipe-jacking and drilling pits, and foundations. We have experience on large projects — power station blocks, gas pipelines up to DN 1000, expressways, weirs and hydroelectric plants — and on smaller investments: residential construction and sewer works.
We run several dozen of our own wellpoint pumps with electric and diesel drives, including sound-insulated units, as well as submersible pumps and motor pumps. As standard we use 32 mm wellpoints (7 m long) and 50 mm wellpoints (4–6 m); larger diameters, up to 100 mm, are possible. We have support equipment — mini-excavators, drilling rigs, tanks and settling tanks for the discharge — and our own transport, and on large jobs we work with a Dutch dewatering company that can supply extra pumps and equipment when needed.
We match the method and the equipment to the ground and water conditions of the particular site — not the other way round. If you only need the equipment, we also offer wellpoint and pump rental.
A question about scope or timing?
Describe your site to us — we will tell you plainly whether and how we can help.
The choice comes down to the ground and water conditions, the depth of the excavation and how long the works run. Below, briefly, where each method fits.
When: ground from sandy gravels down to fine and silty sands, trench and structure excavations
The most common deep dewatering method. Wellpoints are jetted into the ground along the excavation and joined by a suction header to a pump unit. One stage of wellpoints typically lowers the water table by about 4–5 m — no more than 5–6 m, because suction lift sets the limit; deeper excavations use further stages.
When: deep excavations, highly permeable soils, large water inflow
Drilled wells fitted with submersible pumps create a cone of depression covering the whole working area. Chosen where wellpoints cannot reach the required depth or the inflow is too great.
When: small inflow, cohesive soils, short works
Water is collected in sumps at the bottom of the excavation and pumped out with submersible pumps. The simplest and cheapest method, but in loose soils it risks carrying away soil particles and undermining the excavation floor.
Every site is different, but the order of work in wellpoint dewatering is usually the same.
We start by talking about the site: excavation depth, the level the water must be lowered to, the type of ground and the timetable. If there is a geotechnical survey, we base the design on it.
On that basis we choose the method — wellpoints, deep wells or direct pumping — and the number of pumps, the drive and the length of the installation.
Wellpoints are jetted into the ground along the excavation and connected to a suction header, and the header to the pump unit. A delivery pipe carries the water to the agreed discharge point.
Pumping starts ahead of time, so the water is down before the works go below its level. How long that takes depends on the ground and the amount of water.
The installation runs 24 hours a day for as long as work continues below the water table — a break means the water rises in the excavation again.
Once the work below the water table is finished and the excavation backfilled, we dismantle the installation and take the equipment away.
Dewatering changes the water conditions not only in the excavation but around it. We go through these points before we start.
Lowering the water table changes conditions in the ground beyond the excavation too. In compressible soils this can cause settlement of nearby buildings and utilities, so the extent and duration of dewatering are planned with the neighbourhood in mind.
A poorly chosen filter, or direct pumping in loose soils, carries fine soil particles out with the water. The ground loosens and the excavation floor can be disturbed — which is why choosing the wellpoints is not a formality.
When the pumps stop, the water comes back into the excavation, often very quickly, and with water under pressure below the floor it can heave the base. On mains power, have a plan for a supply failure — a diesel-driven pump on standby, for example.
The pumped water has to go somewhere — a storm sewer, a ditch or a watercourse. Discharge is agreed with whoever manages it, and settling tanks are used when the water carries suspended solids.
Under the Polish Water Law (consolidated text: Dz.U. 2025 item 960), permanent dewatering of construction excavations and the discharge of water from excavations require a water-law notification, zgłoszenie wodnoprawne (art. 394(1) points 5 and 8). It is filed with the water supervision office of Wody Polskie before the works begin, and the works may start if the authority raises no objection within 30 days of receiving it (art. 423(2)).
A water-law permit, pozwolenie wodnoprawne, is required among other things for long-term lowering of the groundwater table (art. 389 point 3). The often-quoted test of whether the cone of depression stays within the plot comes from the act in force until the end of 2017 — for excavations the current rules do not use it.
A notification does not replace approvals required under other rules (art. 423(2)). If the water is to go into someone else's water facility, such as a ditch, the owner's consent is attached to the notification (art. 422 point 4). This is a summary of the rules, not legal advice — in a particular case the dewatering design and the authority decide.
The more of this you can give us straight away, the sooner you get a specific answer instead of a general one.
