Dewatering On Construction Sites: What You Need To Know

Safety and practicality should be at the top of your priority list for any construction project. Prior to works commencing, you’ll have several crucial tasks to organise so that engineers and builders can arrive on site on schedule, including dewatering.

Dewatering is an efficient process where solid waste is separated from sludge to temporarily lower groundwater levels. It’s often used where water has accumulated in trenches and excavations, and in areas with a steep slope or high water table.

Why is dewatering important?

Prepares soil

Before construction starts, you want to ensure you have firm foundations on which to build a solid structure. As dewatering removes any excess water, the dry soil stabilizes the ground and reduces the risk of erosion.


Wet or muddy ground can create unsafe working conditions for people on site, resulting in accidents and injuries. Standing water can also be a target for toxins and pests, such as mosquitos.

Stay on schedule

Weather – particularly here in the UK – is notoriously temperamental. During the winter months, the abundance of rain can quickly lead to flooded sites and pockets of standing water; which can damage equipment. Dewatering at the very start will reduce this risk and keep your project on track.

Methods of dewatering

Well Points

Suitable for most ground conditions, well points are a series of shallow wells which are aligned along the excavated area and connected to pipes. Pumps draw out the groundwater to be discharged via a settlement tank.

Deep Wells

The deep well system consists of boreholes with submersible pumps that work to lower the groundwater level, as well as the water table, across the desired area. This method is suited to projects where large volumes need to be removed.

Eductor Wells

Utilising the “venturi effect”, eductor wells use a small volume of water at a high pressure to drive the flow. This technique is particularly effective in deep excavations with low permeability soils.

Precautions to take when dewatering

Dewatering is needed on most construction sites, so it’s important to consider some precautions you should take before getting started.

  • Never pump water directly into sloped areas
  • Avoid dewatering during periods of heavy rainfall
  • Never pump water into areas that are showing signs of erosion
  • Make sure the dewatering surface is surrounded by grass or vegetation
  • Water that has been contaminated should never be discharged

Keeping your site safe is essential to protecting your employees and keeping your project on track. If you’re looking for a robust and easy-to-use tank solution for your dewatering processes, get in touch with our expert team on 01264 243116.

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