A bladder pump is a type of groundwater sampling device used to collect water samples from wells or boreholes for analysis.

It is commonly used in environmental monitoring and assessment to gather information about the quality and characteristics of groundwater.

Here's how a bladder pump groundwater sampling system generally works:

Principle of Operation

A bladder pump operates on the principle of displacement. It uses a flexible bladder or diaphragm to create a vacuum within the pump, which draws water up through the pump and into a collection chamber.

You may also check out our in-depth guide on what is a bladder pump and how to use a bladder pump.


Bladder: The bladder is a flexible, airtight membrane that expands and contracts as the pump operates. It creates a vacuum to pull water into the pump.

    Inlet Valve: The inlet valve is opened to allow groundwater to be drawn into the pump when the bladder expands.
      Outlet Valve: The outlet valve is closed when the bladder expands, preventing water from flowing back into the well during the sampling process.

        Collection Chamber: The collected groundwater is held in the collection chamber for subsequent analysis.



        Sampling Process


        • The bladder pump is lowered into the well or borehole to the desired sampling depth.

        • The pump is then operated by pressurizing the bladder, causing it to expand and create a vacuum. This vacuum draws groundwater into the pump through the inlet valve.

        • Once the pump's collection chamber is filled with groundwater, the bladder is depressurized, and the outlet valve closes, preventing water from flowing back into the well.

        • The bladder pump is then lifted to the surface, and the collected groundwater sample is transferred to sample containers for laboratory analysis.


              • Bladder pumps are suitable for low-flow sampling, minimizing the disturbance of the well and maintaining the integrity of the groundwater sample.
              • They can be used to collect samples from various depths within the well.
              • Bladder pumps can be constructed from materials that are chemically inert, reducing the risk of sample contamination.


                • Proper cleaning and decontamination of the bladder pump before and after each use are crucial to prevent cross-contamination between samples.
                • It's important to use appropriate protocols to ensure accurate and representative groundwater sampling.

                  Remember that specific procedures and equipment may vary based on the manufacturer, the type of bladder pump, and local regulations.

                  Always follow best practices and guidelines for groundwater sampling to obtain reliable and meaningful results for your environmental assessment or monitoring purposes.