A large part of research in the field of unsaturated soil mechanics is focused on cohesive soils due to their distinct capillarity. High suction is controlled and measured in laboratory tests with different techniques, e.g. the axis translation technique or the osmotic technique in combination with pore fluid pressure transducers. In the case of non cohesive soils, such as sands, a lower range of suction is relevant and the chosen methods of suction control should be accurate at very low matric suction. In this contribution a method is presented in which a computer controlled vacuum regulator is applied to impose negative water pressures on a sand specimen. This method allows to control low negative water pressures as occurring in nature for the determination of the soil water characteristic curve (SWCC) or for laboratory tests with controlled suction.