The Geovalve® is a dual function valve for controlling abstraction of groundwater from, and re-injection into, an aquifer while maintaining a constant pressure in the system. The compact design makes it ideal for use in tight boreholes where bi-directional flow is required as it only requires a single line for both functions. The valve provides accurate control of the system pressure so it can also be used simply as an injection valve. The Geovalve® is connected to the discharge of the borehole pump and acts as a non return valve for the off duty pump. The borehole pump must be set at approximately 10 metres below the pumped water level to prevent aeration at the injection point. By injecting water, thus, a positive pressure can be maintained on the complete system. i.e. pipes remain full and no air is allowed into the water.