At construction and infrastructure sites, groundwater often presents an invisible challenge. When an excavation pit fills with water, progress can quickly come to a halt. A dewatering pump provides the solution. This type of pump temporarily lowers the groundwater level so that work can continue safely and efficiently.

In this article, you’ll learn about the various pumps used in dewatering, what a dewatering pump does, how it works, and what to consider when selecting and maintaining one. We’ll also explain why a self-priming pump from Gorman-Rupp is a reliable choice for any dewatering project.

What is a dewatering pump?

A dewatering pump is designed to remove groundwater around an excavation or infrastructure site. The goal is to lower the water level temporarily so the soil remains stable and workable. This process is also commonly known as wellpointing, drainage, dewatering or groundwater control.

The various techniques used in dewatering, requires the use of various types of pumps.

Wellpointing is a technology where a network of vertical filter hoses or wellpoints draw water from the ground. The discharged water is then released into a drain, ditch, or temporary storage area.

(Horizontal-) drainage uses a series of horizontal underground hoses or pipes to extract the water. 

General dewatering refers to pumping surface water from an excavation pit or trench.

Common applications include:

• Foundation and basement construction
• Sewer and utility installations
• Road and railway construction
• Bridge and tunnel works

Depending on the groundwater depth and required flow, different pump types may be used.

Types of dewatering pumps

Self-priming pumps

These pumps can handle air and water simultaneously, and are the preferred choice when the water supply to the pump is intermittent. Gorman-Rupp offers wet- and dry self-priming pumps for this. The latter works with an additional vacuum priming pump, often also referred to as prime-assisted pumps.

Self-priming pumps are ideal for dewatering because they start quickly, require minimal maintenance, and are resistant to debris and solids. Moreover they offer high flow capacity, enabling fast dewatering.

Advantages:

• Automatic priming, even in dry conditions
• Rugged construction for continuous operation
• High flow design
• High reliability and easy access for service

Diaphragm pumps

A diaphragm pump uses a flexible membrane to draw and discharge water. It’s often used for small-scale or temporary dewatering projects.
This type performs well with heavily contaminated water, for example on muddy or silty sites.

Piston pumps

A piston pump uses one or multiple reciprocating pistons. On the suction stroke, water is primed into the cylinder and upon the discharge stroke, the water is pressurised and discharged.

This type of pump is commonly used for vertical well pointing, due to the pump delivering a high vacuum. The low discharge capacity makes them less suitable for other dewatering jobs where self-priming centrifugal- or membrane pumps are more suitable.

Submersible pumps

For deep excavations, a submersible pump may be used. It operates directly in the water and continuously removes groundwater. These pumps are effective at greater depths but require more maintenance and electrical power.

How a dewatering pump works

A standard dewatering setup consists of the following key components:

1. Wellpoints, horizontal filter tubes or suction piping installed in the ground or the well to collect water
2. A vacuum header pipe or hoses connected to the pump
3. The dewatering pump itself, which discharges the water
4. Discharge piping, often consisting of flexible hoses or rigid piping or a combination of these.

The pump creates a vacuum in the pipe network, drawing water from the source. The discharged water is typically pumped into surrounding surface water , or reused for dust suppression or irrigation.

A self-priming centrifugal pump from Gorman-Rupp can handle both air and water, ensuring a stable operation even under fluctuating conditions. This makes it ideal for construction sites that demand high flow rates, high reliability and uptime.

When to choose a dewatering pump

A dewatering pump is essential whenever groundwater interferes with excavation, foundation, or utility work. Key factors to consider include:

• The type of dewatering technique used in your project
• Soil type: sand, clay, or peat affect suction capacity and filtration.
• Water level and flow rate: high groundwater or large flows require stronger pumps.
• Project duration: for long-term use, an efficient pump with low maintenance costs pays off.
• Water quality: trash-handling pumps prevent clogging in dirty conditions.

Gorman-Rupp pumps are known for their high availability and service-friendly design. Thanks to their self-priming system, they require fewer interventions and deliver consistent performance throughout the project.

Importance of regular maintenance

Proper maintenance extends the life of a dewatering pump and prevents costly downtime.
Routine service should include:

• Checking hoses, seals, and valves
• Cleaning the casing and impeller
• Monitoring oil levels and shaft seals
• Inspecting filters and check valves

It’s recommended to have maintenance carried out by trained technicians. This ensures safety, energy efficiency, and reliable operation for future projects.

Advantages of Gorman-Rupp dewatering pumps

Gorman-Rupp pumps are built for performance and durability.
Main benefits include:

• Fast priming and high efficiency with dry self-priming design
• Minimal maintenance due to easy-access pump housing
• Long service life with quality materials and robust construction
• Handles solids and harsh conditions without clogging

These qualities make Gorman-Rupp pumps ideal for construction, industrial, and municipal dewatering projects where uptime and dependability are critical.

Conclusion

A dewatering pump is essential for any project where groundwater obstructs progress. The right pump selection determines both the efficiency and continuity of operations.
Gorman-Rupp’s self-priming centrifugal pumps provide the perfect combination of performance, reliability, and ease of maintenance. Their solid design and straightforward operation make them suitable for long-term, heavy-duty use.

Whether you’re working on an excavation, infrastructure project, or industrial site, a well-chosen dewatering pump helps you work safely, efficiently, and dry.