A local contractor contacted us partway through a project where they were trying to dewater a set of foundations, before installing the rebar and pouring concrete. This is a problem which is certainly not unusual in winter, with excavations often filling with water.
On paper it should have been a fairly straightforward job, however the nature of the soil and dig made it very difficult with a "normal" submersible pump, often known by contractors as “sub pumps”.
Their pumps slowed down, clogged, and stopped pumping anything meaningful from the trenches. The water was full of fine silt and loose soil from the excavation, and it settled around the inlet of the pumps quickly, such that they struggled to empty the water. The moment the solids settled, the pumps were fighting a losing battle. The team were spending more time restarting equipment and clearing intakes than they were actually pumping.
At this point, we were asked for advice and recommended the Evak Trenchman. It’s a site pump built for this exact environment. The key difference with this model of water pump is the built-in sintered agitator. Instead of sitting passively in the water, the agitator helps churn the mixture so the silts and fines don’t settle as the water is pumped. Keeping the solids suspended means the pump can move the water rather than sitting in a puddle of sludge.
The contractor replaced their standard submersible water pump, and used the EVAK Trenchman. This allowed the water in the foundations to be pumped away, allowing the rebar to go in and the concrete to be poured.
It’s a good example of why the right pump specification matters. On sites like this, the challenge isn’t just removing water. It’s dealing with everything that comes with it. The Trenchman was ideal, it’s worth choosing a pump that’s built for the reality of site conditions rather than the theory. Available in various models and power outputs, in this instance the smallest model was chosen, the EVAK Trenchman 400A 110v, as the dig was for a relatively small extension.
In property-level protection schemes, barriers may seal doors and openings, but water can still enter through walls, floors, and service routes. Measures like repointing or tanking reduce this, but rarely eliminate it entirely.
The EGO 500 SELS uses electronic water-sensing probes rather than a traditional float switch. This allows low level automatic operation in shallow sumps or tight chambers where floats may otherwise jam, or stick - whilst also not pumping as low...
If it’s a critical part of your flood resilience setup, treat it like any other critical bit of kit:
accessible, serviceable, protected, and backed‑up.
